A 45-year-old alcoholic man presents with severe epigastric pain radiating to the back. Serum amylase is mildly elevated; lipase is markedly elevated. Which pathophysiologic event best explains his pain?
A. Gastric acid hypersecretion
B. Activation of pancreatic zymogens within the pancreas
C. Autoimmune destruction of pancreatic β-cells
D. Obstruction of the common bile duct by stone
Answer: B. Activation of pancreatic zymogens within the pancreas.
Explanation: Premature intrapancreatic activation of trypsinogen → autodigestion and inflammation causing severe epigastric pain.
A patient with long-standing GERD develops Barrett esophagus. Which epithelial change occurs?
A. Stratified squamous → columnar (intestinal) with goblet cells
B. Columnar → stratified squamous
C. Simple cuboidal → pseudostratified columnar
D. Columnar → transitional epithelium
Answer: A. Stratified squamous → columnar (intestinal) with goblet cells.
Explanation: Chronic acid exposure leads to metaplasia: squamous → columnar intestinalized mucosa with goblet cells, increasing adenocarcinoma risk.
A 30-year-old woman presents with watery diarrhea and flushing. Serum vasoactive intestinal peptide (VIP) is elevated. Which acid/base disturbance is expected?
A. Metabolic acidosis with low bicarbonate
B. Metabolic alkalosis with high bicarbonate
C. Metabolic acidosis with high bicarbonate
D. Metabolic alkalosis with low chloride
Answer: A. Metabolic acidosis with low bicarbonate.
Explanation: VIPoma causes secretory diarrhea → bicarbonate loss → non-anion gap metabolic acidosis.
During intestinal absorption, which transporter at the apical enterocyte membrane is primarily responsible for sodium-coupled glucose uptake?
A. GLUT2
B. SGLT1
C. Na+/K+ ATPase
D. PEPT1
Answer: B. SGLT1.
Explanation: SGLT1 cotransports 2 Na⁺ with 1 glucose into enterocytes (apical); basolateral GLUT2 moves glucose into blood.
A 65-year-old with cirrhosis develops asterixis and confusion. Which metabolic derangement primarily contributes to his encephalopathy?
A. Hypoglycemia
B. Hyperammonemia
C. Hyponatremia
D. Hyperkalemia
Answer: B. Hyperammonemia.
Explanation: Impaired hepatic urea cycle → elevated ammonia crosses BBB altering neurotransmission and causing encephalopathy.
A colon biopsy shows transmural inflammation with noncaseating granulomas. The most likely diagnosis is:
A. Ulcerative colitis
B. Crohn disease
C. Ischemic colitis
D. Infectious colitis
Answer: B. Crohn disease.
Explanation: Crohn’s: transmural, skip lesions, granulomas; UC is mucosal, continuous, starts at rectum.
A patient has painless jaundice and weight loss. Murphy’s sign is negative. Which malignancy most classically causes painless obstructive jaundice?
A. Pancreatic head adenocarcinoma
B. Gallbladder carcinoma
C. Hepatocellular carcinoma
D. Duodenal adenoma
Answer: A. Pancreatic head adenocarcinoma.
Explanation: Tumor at pancreatic head obstructs distal bile duct → painless progressive cholestatic jaundice.
A 28-year-old with chronic pancreatitis has steatorrhea and fat-soluble vitamin deficiency. Which is the primary reason for steatorrhea?
A. Decreased pancreatic lipase secretion
B. Increased gastric acid secretion
C. Small bowel bacterial overgrowth
D. Reduced bile acid synthesis
Answer: A. Decreased pancreatic lipase secretion.
Explanation: Loss of exocrine pancreatic function → impaired triglyceride digestion → fatty stools and malabsorption.
A 55-year-old presents with bright red blood per rectum and hemodynamic instability. Which vascular lesion in the colon is most associated with painless massive bleeding in elderly patients?
A. Hemorrhoids
B. Angiodysplasia of the cecum/ascending colon
C. Diverticulosis of sigmoid colon
D. Ischemic colitis
Answer: B. Angiodysplasia of the cecum/ascending colon.
Explanation: Angiodysplasia—dilated submucosal veins—causes painless intermittent bleeding in elderly, esp. right colon.
A patient with autoimmune hepatitis has anti-smooth muscle and anti-nuclear antibodies and elevated ALT/AST. Which histologic feature is most typical?
A. Interface hepatitis (piecemeal necrosis) with lymphoplasmacytic infiltrate
B. Caseating granulomas
C. Mallory bodies with steatosis
D. Fatty change only
Answer: A. Interface hepatitis (piecemeal necrosis) with lymphoplasmacytic infiltrate.
Explanation: Autoimmune hepatitis shows portal inflammation spilling into periportal hepatocytes with plasma cells.
A 45-year-old has peptic ulcer disease refractory to proton pump inhibitors (PPIs). H. pylori eradication therapy fails. Which genetic trait increases risk for PPI toxicity and therapeutic failure?
A. CYP2C19 rapid metabolizer phenotype
B. HLA-B27 positivity
C. IL-1β polymorphism
D. BRCA1 mutation
Answer: A. CYP2C19 rapid metabolizer phenotype.
Explanation: PPIs are metabolized by CYP2C19; rapid metabolizers clear PPIs faster, reducing efficacy for acid suppression.
A stool sample shows trophozoites with a sucking disc; patient has foul, greasy diarrhea. Which organism?
A. Entamoeba histolytica
B. Giardia lamblia
C. Cryptosporidium parvum
D. Cyclospora cayetanensis
Answer: B. Giardia lamblia.
Explanation: Giardia attaches to mucosa with adhesive disc, causes malabsorption and bulky, greasy stools.
A 60-year-old with chronic hepatitis B infection has elevated alpha-fetoprotein (AFP). Which imaging finding suggests hepatocellular carcinoma?
A. Single enhancing mass with arterial phase hyperenhancement and venous washout
B. Multiple hypodense lesions with peripheral rim enhancement only
C. Diffuse fatty infiltration without mass
D. Cavernous hemangioma with uniform enhancement
Answer: A. Single enhancing mass with arterial phase hyperenhancement and venous washout.
Explanation: HCC classically shows arterial hyperenhancement and washout on venous phase; AFP often elevated.
A child presents with failure to thrive, bulky foul stools, and nasal polyps. Which sweat chloride and stool test findings are expected?
A. Low sweat Cl⁻, positive stool reducing substances
B. High sweat Cl⁻, elevated fecal elastase (low malabsorption)
C. High sweat Cl⁻, low fecal elastase (pancreatic insufficiency)
D. Normal sweat Cl⁻, low fecal fat only
Answer: C. High sweat Cl⁻, low fecal elastase (pancreatic insufficiency).
Explanation: Cystic fibrosis → defective CFTR → high sweat chloride, exocrine pancreatic insufficiency → low fecal elastase and steatorrhea.
A 50-year-old man has jaundice, pruritus, and pale stools. Labs show high alkaline phosphatase and conjugated bilirubin. Which diagnosis is most likely?
A. Intrahepatic cholestasis (e.g., PSC/ PBC) or extrahepatic obstruction; common bile duct obstruction causes these labs
B. Gilbert syndrome
C. Hemolytic anemia
D. Crigler-Najjar syndrome
Answer: A. Extrahepatic obstruction / cholestasis.
Explanation: Elevated ALP and conjugated bilirubin with pale stools and pruritus indicate obstructive/cholestatic jaundice (e.g., bile duct obstruction).
A patient with elevated gastrin levels and refractory peptic ulcers is suspected to have a gastrinoma. Which diagnostic test is most specific?
A. Serum gastrin at random
B. 72-hour secretin stimulation test with paradoxical gastrin rise
C. Esophagogastroduodenoscopy (EGD) with biopsy only
D. Urea breath test
Answer: B. Secretin stimulation test with paradoxical gastrin rise.
Explanation: Gastrinoma (Zollinger-Ellison) shows paradoxical rise in gastrin after secretin; imaging localizes tumor.
A newborn fails to pass meconium in first 48 hours and has abdominal distention. Rectal biopsy reveals absence of ganglion cells in submucosa and myenteric plexus. Which embryologic failure explains this?
A. Neural crest migration failure (Hirschsprung disease)
B. Failure of foregut rotation
C. Agenesis of dorsal pancreatic bud
D. Failure of midgut retraction
Answer: A. Neural crest migration failure.
Explanation: Hirschsprung disease results from absent neural crest–derived ganglion cells → tonic contraction and obstruction.
A 24-hour stool collection shows increased fecal fat and increased stool weight after pancreatic resection. Which lab value would best document fat malabsorption?
A. Increased fecal alpha-1 antitrypsin
B. Increased fecal elastase (decreased in insufficiency)
C. Increased 72-hour fecal fat >7 g/day
D. Positive fecal occult blood
Answer: C. Increased 72-hour fecal fat >7 g/day.
Explanation: Quantitative 72-hour fecal fat measures steatorrhea; >7 g/day indicates malabsorption.
A patient with autoimmune destruction of intrahepatic bile ducts (pruritus, xanthelasma) is most likely to have which autoantibody?
A. Anti-mitochondrial antibody (AMA)
B. Anti-smooth muscle antibody
C. Anti-tTG antibody
D. Anti-endomysial antibody
Answer: A. Anti-mitochondrial antibody (AMA).
Explanation: Primary biliary cholangitis (PBC) is associated with AMA and progressive cholestasis, mainly in middle-aged women.
A 39-year-old with Crohn disease develops kidney stones composed of calcium oxalate. Which mechanism predisposes to oxalate nephrolithiasis?
A. Increased intestinal oxalate absorption due to fat binding calcium → free oxalate absorption
B. Hyperparathyroidism
C. Excess vitamin D intake
D. Low urinary citrate exclusively
Answer: A. Increased intestinal oxalate absorption due to fat binding calcium.
Explanation: Fat malabsorption → unabsorbed fatty acids bind Ca²⁺ → leave free oxalate to be absorbed and form renal stones.
A 57-year-old woman has severe pruritus and cholestatic LFTs; antimitochondrial antibodies are negative; she has inflammatory bowel disease. Which diagnosis is most likely?
A. Primary sclerosing cholangitis (PSC) associated with IBD
B. Primary biliary cholangitis (PBC)
C. Alcoholic hepatitis
D. Choledocholithiasis
Answer: A. Primary sclerosing cholangitis.
Explanation: PSC is associated with ulcerative colitis, causes cholestasis and beading of intra/extrahepatic ducts on ERCP.
A 68-year-old with long-standing reflux and a 3-cm ulcerated distal esophageal mass; biopsy shows glandular dysplasia and invasive adenocarcinoma. Which risk factor most likely contributed?
A. Barrett esophagus from chronic GERD
B. H. pylori infection in stomach
C. Achalasia
D. Plummer-Vinson syndrome
Answer: A. Barrett esophagus from chronic GERD.
Explanation: Barrett esophagus predisposes to esophageal adenocarcinoma in distal esophagus.
A 3-year-old child with recurrent giardiasis has low IgA. Which immune defect explains increased susceptibility to mucosal infections?
A. Selective IgA deficiency
B. Severe combined immunodeficiency
C. Hyper-IgM syndrome
D. Common variable immunodeficiency
Answer: A. Selective IgA deficiency.
Explanation: IgA is critical for mucosal immunity; deficiency causes recurrent GI and respiratory infections.
A patient with peptic ulcer disease has a positive urea breath test. What is the pathogenetic mechanism by which this organism induces ulcers?
A. Urease production neutralizes gastric acid and allows colonization; chronic inflammation predisposes to mucosal damage
B. Direct toxin that destroys parietal cells only
C. Produces insulin-like growth factor
D. Systemic vasculitis causing ischemic ulcers
Answer: A. Urease production neutralizes gastric acid and allows colonization; chronic inflammation predisposes to mucosal damage.
Explanation: H. pylori urease creates alkaline microenvironment; bacterial factors and host response lead to gastritis and peptic ulceration.
A 45-year-old obese woman has GERD and hiatal hernia causing reflux. Which anatomic factor contributes to reflux in sliding hiatal hernia?
A. Proximal stomach and gastroesophageal junction move into thorax through widened hiatus
B. Rotation of midgut during development
C. Weakness of lower esophageal muscle due to vagal paralysis
D. Esophageal atresia
Answer: A. Proximal stomach and gastroesophageal junction move into thorax.
Explanation: Sliding hiatal hernia: stomach and GE junction herniate upward, impairing LES function and promoting reflux.
A patient with cholestatic liver disease has elevated conjugated bilirubin in blood and pale stools. Where is conjugated bilirubin normally excreted?
A. Urine only
B. Bile into intestines via bile canaliculi
C. Reabsorbed into portal vein directly
D. Stored in kidney tubules
Answer: B. Bile into intestines via bile canaliculi.
Explanation: Conjugated bilirubin is water-soluble and excreted into bile; obstruction prevents delivery to intestine → pale stools.
A patient with acute mesenteric ischemia has severe abdominal pain out of proportion to exam. Which vessel occlusion most commonly causes acute small bowel ischemia?
A. Superior mesenteric artery (SMA) embolus/thrombosis
B. Inferior mesenteric artery
C. Celiac trunk
D. Portal vein
Answer: A. Superior mesenteric artery.
Explanation: SMA supplies midgut (small intestine); embolic/thrombotic occlusion causes acute severe pain and ischemia.
A 52-year-old with iron deficiency anemia and positive FOBT undergoes colonoscopy revealing a polyp with villous architecture and severe dysplasia. Which polyp type carries highest malignant potential?
A. Hyperplastic polyp
B. Tubular adenoma
C. Villous adenoma
D. Hamartomatous polyp
Answer: C. Villous adenoma.
Explanation: Villous adenomas (villous > tubular) have higher risk of progression to carcinoma, esp. large size and high-grade dysplasia.
A patient with hepatitis C develops mixed cryoglobulinemia causing palpable purpura and glomerulonephritis. Cryoglobulins precipitate at low temperature and are composed of:
A. Immune complexes (IgM with rheumatoid factor activity and polyclonal IgG)
B. Pure fibrin only
C. Native RBC aggregates
D. Lipoprotein aggregates
Answer: A. Immune complexes (IgM with RF activity and polyclonal IgG).
Explanation: Mixed cryoglobulinemia is immune complex–mediated vasculitis associated with HCV.
A 40-year-old with chronic pancreatitis gets an endocrine insufficiency manifesting as diabetes mellitus. Which cells are lost in chronic pancreatitis causing diabetes?
A. Alpha cells
B. Beta cells (islets of Langerhans)
C. Acinar cells only
D. Ductal cells exclusively
Answer: B. Beta cells.
Explanation: Chronic destruction/fibrosis of pancreas damages islets causing insulin deficiency and diabetes.
A 26-year-old presents with severe watery diarrhea after travel. Stool testing reveals acid-fast oocysts. Which organism?
A. Giardia lamblia
B. Cryptosporidium parvum
C. Entamoeba histolytica
D. Vibrio cholerae
Answer: B. Cryptosporidium parvum.
Explanation: Crypto oocysts are acid-fast; causes profuse watery diarrhea especially in immunocompromised.
A patient with malabsorption has deficiency of vitamin B12 despite adequate intake. Which anatomic lesion can cause B12 malabsorption?
A. Resection of terminal ileum
B. Resection of duodenum only
C. Gastric fundus resection spares intrinsic factor
D. Colonic resection
Answer: A. Resection of terminal ileum.
Explanation: B12–IF complex is absorbed in terminal ileum; resection or disease (Crohn) causes deficiency.
A 65-year-old man with long-term ulcerative colitis undergoes colonoscopy for dysplasia surveillance. Which pattern of colorectal cancer is classically seen in UC?
A. Multifocal, pancolonic risk with dysplasia–carcinoma sequence
B. Single isolated polyp adenoma only
C. Right-sided adenocarcinoma more than left
D. Small bowel adenocarcinoma predominance
Answer: A. Multifocal, pancolonic risk with dysplasia–carcinoma sequence.
Explanation: UC predisposes to flat dysplasia and multifocal adenocarcinomas; risk correlates with disease duration and extent.
A 50-year-old man has painless jaundice and Courvoisier sign (palpable non-tender gallbladder). Which cause is most likely?
A. Carcinoma of the head of the pancreas causing extrahepatic biliary obstruction
B. Acute viral hepatitis
C. Hemolytic anemia
D. Gilbert syndrome
Answer: A. Carcinoma of the pancreatic head.
Explanation: Tumor obstructs distal bile duct → painless obstructive jaundice with palpable GB (Courvoisier).
A patient presents with acute viral hepatitis. Which serologic marker indicates acute infection with hepatitis B virus?
A. HBsAg and IgM anti-HBc (core IgM)
B. Anti-HBs only
C. HBeAg only with no other markers
D. Anti-HBc IgG only
Answer: A. HBsAg and IgM anti-HBc.
Explanation: HBsAg indicates infection; IgM anti-HBc denotes recent/acute infection.
A 60-year-old alcoholic with ascites has spontaneous bacterial peritonitis. Which organism is most commonly the cause?
A. E. coli (enteric gram-negatives)
B. Group A streptococcus
C. Staphylococcus aureus
D. Candida albicans
Answer: A. E. coli.
Explanation: Spontaneous bacterial peritonitis commonly due to translocation of enteric organisms like E. coli.
A patient has a history of hepatomegaly, bronzing skin, and diabetes. Which hereditary disorder is most likely?
A. Hereditary hemochromatosis (HFE mutation) causing iron overload
B. Wilson disease (copper accumulation)
C. Alpha-1 antitrypsin deficiency
D. Gilbert syndrome
Answer: A. Hereditary hemochromatosis.
Explanation: Triad of cirrhosis, diabetes, bronze skin; increased iron deposition in organs.
A 6-month-old baby presents with projectile, nonbilious vomiting and a palpable olive mass in the RUQ. What is the most likely diagnosis?
A. Pyloric stenosis (hypertrophic pyloric obstruction)
B. Duodenal atresia
C. Malrotation with volvulus
D. Intussusception
Answer: A. Pyloric stenosis.
Explanation: Hypertrophic pyloric muscle obstruction causes nonbilious projectile vomiting and palpable pyloric mass.
A patient with autoimmune gastritis is at increased risk for which neoplasm?
A. Gastric adenocarcinoma and gastric carcinoid (neuroendocrine) due to chronic atrophic gastritis and hypergastrinemia
B. Esophageal squamous cell carcinoma only
C. Small cell carcinoma of lung
D. Hepatocellular carcinoma
Answer: A. Gastric adenocarcinoma and gastric carcinoid.
Explanation: Autoimmune gastritis → chronic atrophy, achlorhydria, hypergastrinemia (ECL hyperplasia) → carcinoid and adenocarcinoma risk.
A patient with chronic liver disease is found to have esophageal varices. Which portal pressure change is primarily responsible?
A. Increased portal venous pressure due to portal hypertension from cirrhosis
B. Increased hepatic venous outflow only
C. Systemic hypertension
D. Lymphatic obstruction
Answer: A. Increased portal venous pressure due to portal hypertension.
Explanation: Fibrosis increases resistance to portal flow → varices form as collateral pathways.
A 30-year-old woman has severe epigastric pain worse after meals; endoscopy shows gastric ulcer with hypertrophied gastric folds and elevated gastrin. Which cause is likely?
A. Gastrinoma (Zollinger-Ellison syndrome)
B. H. pylori antral gastritis alone
C. Viral gastroenteritis
D. NSAID use only
Answer: A. Gastrinoma.
Explanation: Gastrin-secreting tumor causes acid hypersecretion, refractory ulcers, and hypertrophic gastric folds.
A patient is positive for anti-tissue transglutaminase antibodies and has villous atrophy on duodenal biopsy. Which extraintestinal manifestation is strongly associated?
A. Dermatitis herpetiformis and iron deficiency anemia
B. Recurrent pancreatitis only
C. Hepatomegaly only
D. Pulmonary fibrosis only
Answer: A. Dermatitis herpetiformis and iron deficiency anemia.
Explanation: Celiac disease causes malabsorption (iron deficiency) and IgA-mediated skin lesions (DH).
A 70-year-old with long-standing GERD develops dysphagia and weight loss. Endoscopy reveals a long circumferential distal esophageal lesion; biopsy shows columnar dysplasia with intestinal metaplasia. What is the management concern?
A. High risk of progression to adenocarcinoma → surveillance/therapy indicated
B. Reassure; no cancer risk
C. Treat with antibiotics only
D. Strong association with squamous cell carcinoma instead
Answer: A. High risk of progression to adenocarcinoma.
Explanation: Barrett esophagus with dysplasia carries malignant potential; endoscopic surveillance and therapy.
A patient with obstructive jaundice has conjugated hyperbilirubinemia and pale stools. Which bile constituent will be decreased in the stool leading to pale stools?
A. Stercobilin (urobilinogen oxidized form in stool)
B. Bilirubin unmodified
C. Urobilinogen in urine only
D. Biliverdin only
Answer: A. Stercobilin.
Explanation: Obstruction prevents bilirubin excretion; lack of stercobilin causes pale stools.
A 22-year-old presents with severe abdominal pain, arthralgias, and bloody diarrhea; colon biopsy shows transmural inflammation and fissuring ulcers. Which extraintestinal complication is he at increased risk for?
A. Primary sclerosing cholangitis and cholangiocarcinoma (UC more than Crohn’s) — but transmural with fissures indicates Crohn so risk of malabsorption and fistulae.
B. Cholangiocarcinoma only
C. Hepatocellular carcinoma only
D. Appendicitis only
Answer: A (context nuance).
Explanation: Crohn’s (transmural) predisposes to fistulae, strictures, and malabsorption; UC (continuous mucosal) is strongly linked to PSC and cholangiocarcinoma.
A patient with chronic alcohol abuse has macrocytic anemia and elevated MCV due to poor nutrition and alcohol toxicity. Which mechanism primarily causes macrocytosis in alcoholism?
A. Direct toxic effect on bone marrow and folate deficiency impairing DNA synthesis
B. Iron deficiency only
C. Hemolysis exclusively
D. Vitamin B12 overabsorption
Answer: A. Direct marrow toxicity and folate deficiency.
Explanation: Alcohol suppresses marrow and causes folate deficiency → impaired DNA synthesis → macrocytosis.
A 52-year-old with a history of peptic ulcer disease presents with sudden severe abdominal pain and free air under diaphragm on x-ray. What is the most likely diagnosis?
A. Perforated peptic ulcer (visceral perforation causing pneumoperitoneum)
B. Mesenteric ischemia
C. Intussusception
D. Small bowel obstruction without perforation
Answer: A. Perforated peptic ulcer.
Explanation: Peptic ulcer perforation causes pneumoperitoneum and acute abdomen.
A patient with H. pylori infection is at increased risk for which gastric neoplasm types?
A. Gastric adenocarcinoma and MALT lymphoma
B. Esophageal adenocarcinoma only
C. Pancreatic carcinoma only
D. Hepatocellular carcinoma only
Answer: A. Gastric adenocarcinoma and MALT lymphoma.
Explanation: Chronic H. pylori gastritis predisposes to intestinal-type gastric adenocarcinoma and extranodal marginal zone lymphoma (MALT).
A newborn with bilious vomiting and abdominal distention has double bubble sign on abdominal x-ray. Which diagnosis is most likely?
A. Duodenal atresia (or annular pancreas)
B. Pyloric stenosis
C. Hirschsprung disease
D. Meconium ileus
Answer: A. Duodenal atresia.
Explanation: Double bubble (stomach + proximal duodenum) indicates proximal small bowel obstruction like duodenal atresia; often associated with Down syndrome.
A patient develops acute cholangitis with Charcot triad (fever, RUQ pain, jaundice). What is the most important immediate management step?
A. Prompt biliary decompression (ERCP) and antibiotics
B. Start lactulose only
C. Immediate liver transplant
D. High-dose PPI alone
Answer: A. Prompt biliary decompression (ERCP) and antibiotics.
Explanation: Ascending cholangitis is life-threatening; urgent biliary drainage and broad-spectrum antibiotics are required.
51 . A 34-year-old presents with episodic right upper-quadrant pain after fatty meals. Ultrasound shows gallstones. Which mechanism best explains the pain?
A. Distension of hepatic capsule
B. Passive bile reflux into pancreatic duct
C. Gallbladder contraction against an obstructed cystic duct
D. Rapid emptying of bile into duodenum
Correct: C
Explanation: Postprandial cholecystokinin causes gallbladder contraction; a stone in the cystic duct causes acute biliary colic.
A chronic HCV patient has progressive liver dysfunction. Which long-term sequence is most expected?
A. Steatosis → metabolic alkalosis → portal hypertension
B. Steatosis → inflammation → fibrosis → cirrhosis
C. Hepatocyte necrosis → cholelithiasis → cholangitis
D. Portal thrombosis → hepatocellular failure → pancreatitis
Correct: B
Explanation: Chronic viral hepatitis leads to inflammation and progressive fibrosis, culminating in cirrhosis and HCC risk.
A 7-year-old presents with colicky abdominal pain and currant-jelly stools. Ultrasound confirms intussusception. What is the typical lead point in this age group?
A. Meckel diverticulum
B. Hypertrophied Peyer patches
C. Lipoma in the colon
D. Cecal carcinoma
Correct: B
Explanation: Viral illnesses enlarge Peyer patches, predisposing children to ileocecal intussusception.
A patient develops steatorrhea after a segmental ileal resection. What best explains the fat malabsorption?
A. Loss of gastric parietal cells
B. Impaired bile acid reabsorption
C. Reduced pancreatic enzyme secretion
D. Excessive intestinal motility
Correct: B
Explanation: Bile acids are reabsorbed in the ileum; loss reduces micelle formation → steatorrhea.
A patient begins therapy for confirmed H. pylori infection. Which regimen is standard first-line?
A. PPI + clarithromycin + amoxicillin
B. Bismuth alone
C. Metronidazole alone
D. PPI + tetracycline only
Correct: A
Explanation: Clarithromycin-based triple therapy is a standard regimen in regions with low macrolide resistance.
A cirrhotic patient has splenomegaly and thrombocytopenia. What mechanism explains this?
A. Autoimmune platelet destruction
B. Bone marrow suppression
C. Platelet sequestration in an enlarged spleen
D. Vitamin B12 deficiency
Correct: C
Explanation: Portal hypertension causes splenic congestion → increased sequestration of platelets.
A 72-year-old presents with painless hematochezia. Colonoscopy reveals angiodysplasia. Which comorbidity is classically associated?
A. Aortic stenosis
B. Diabetes mellitus
C. Hypothyroidism
D. COPD
Correct: A
Explanation: Aortic stenosis is linked with increased risk of angiodysplasia (Heyde syndrome).
A patient reports black tarry stools. Which location best explains melena?
A. Rectum
B. Sigmoid colon
C. Jejunum
D. Stomach
Correct: D
Explanation: Melena usually indicates an upper GI bleed proximal to ligament of Treitz.
A Crohn disease patient has fatigue and pallor. Lab work shows iron deficiency anemia. Most likely cause?
A. Decreased gastric acid secretion
B. Chronic intestinal blood loss
C. Vitamin K deficiency
D. Excess copper absorption
Correct: B
Explanation: Crohn disease leads to mucosal ulceration → chronic blood loss + malabsorption of iron.
A newborn presents with nonbilious projectile vomiting. Labs?
A. Hyperchloremic acidosis
B. Hypochloremic metabolic alkalosis
C. Hyperkalemia with acidosis
D. Hyponatremic metabolic acidosis
Correct: B
Explanation: Pyloric stenosis causes vomiting → loss of HCl → metabolic alkalosis and low chloride.
A patient with NAFLD shows elevated ALT > AST. What early hepatic change is hallmark?
A. Hepatocyte necrosis
B. Macrovesicular steatosis
C. Microvesicular steatosis
D. Kupffer cell hypertrophy
Correct: B
Explanation: NAFLD begins with reversible macrovesicular fat accumulation.
A 55-year-old alcoholic presents with severe epigastric pain radiating to the back. Serum lipase is elevated. What complication may follow?
A. Hypocalcemia due to fat necrosis
B. Hyperbilirubinemia from hemolysis
C. Hyperkalemia from acidosis
D. Portal vein thrombosis
Correct: A
Explanation: Pancreatitis causes fat necrosis binding Ca²⁺ → hypocalcemia.
A patient with long-standing GERD undergoes biopsy showing intestinal-type mucosa with goblet cells in the esophagus. What is this change?
A. Dysplasia
B. Hyperplasia
C. Barrett metaplasia
D. Fibrosis
Correct: C
Explanation: Squamous → columnar intestinal metaplasia defines Barrett esophagus.
A 45-year-old with chronic pancreatitis has bulky greasy stools. Mechanism?
A. Loss of pancreatic duct secretin receptors
B. Pancreatic insufficiency due to acinar destruction
C. Hepatic fibrosis
D. Impaired gastric motility
Correct: B
Explanation: Chronic pancreatitis destroys acinar cells → ↓ lipase → steatorrhea.
A patient presents with severe hematemesis. He has portal hypertension. What vessel is most likely the source?
A. Left gastric vein → esophageal varices
B. Inferior mesenteric vein
C. Right gastric artery
D. Splenic artery
Correct: A
Explanation: Portal HTN causes esophageal varices via left gastric vein.
A 68-year-old has progressive dysphagia first to liquids then solids. Barium swallow shows "bird-beak" narrowing. Diagnosis?
A. Esophageal varices
B. Achalasia
C. Zenker diverticulum
D. Schatzki ring
Correct: B
Explanation: Achalasia = LES failure + aperistalsis → bird-beak appearance.
A patient with celiac disease continues to have symptoms. Which antibody is most specific?
A. Anti-mitochondrial antibodies
B. Anti-gliadin antibodies
C. Anti–tissue transglutaminase (tTG) IgA
D. Anti–smooth muscle antibodies
Correct: C
Explanation: Anti-tTG IgA is highly sensitive and specific for celiac disease.
A 32-year-old female with gallstones develops Charcot triad. What is this triad?
A. Fever, RUQ pain, jaundice
B. Fever, hypotension, anemia
C. Jaundice, splenomegaly, ascites
D. Abdominal pain, vomiting, melena
Correct: A
Explanation: Charcot triad = ascending cholangitis.
A 45-year-old with ulcerative colitis develops toxic megacolon. What is the major risk?
A. Renal failure
B. Perforation
C. Pancreatitis
D. Gallstone formation
Correct: B
Explanation: Dilated colon wall becomes thin → high risk of perforation.
A 58-year-old chronic smoker has progressive dysphagia and weight loss. Biopsy shows squamous cell carcinoma of esophagus. Risk factor?
A. H. pylori
B. Barrett esophagus
C. Smoking and alcohol
D. Celiac disease
Correct: C
Explanation: SCC of esophagus strongly associated with alcohol + smoking.
A newborn fails to pass meconium within 48 hours and has explosive stool upon rectal exam. Likely diagnosis?
A. Pyloric stenosis
B. Hirschsprung disease
C. Duodenal atresia
D. Anal fissure
Correct: B
Explanation: Lack of ganglion cells → failure of relaxation → obstructive constipation.
A patient with Crohn disease develops kidney stones. Which type is common?
A. Calcium phosphate
B. Uric acid
C. Struvite
D. Calcium oxalate
Correct: D
Explanation: Fat malabsorption → free fatty acids bind Ca²⁺ → ↑ oxalate absorption.
A man with cirrhosis presents with confusion and asterixis. What precipitating factor is common?
A. High-protein diet
B. High-fat diet
C. Excess coffee intake
D. Iron deficiency
Correct: A
Explanation: Protein → ↑ ammonia → hepatic encephalopathy.
A 45-year-old with peptic ulcer disease responds well to PPI therapy. What is the primary mechanism of PPIs?
A. Block H₂ receptors
B. Irreversible inhibition of H⁺/K⁺ ATPase
C. Increase gastric mucus secretion
D. Neutralize gastric acid chemically
Correct: B
Explanation: PPIs block the final step of acid secretion.
A patient develops jaundice with dark urine and pale stools. Labs show elevated conjugated bilirubin. Possible cause?
A. Hemolysis
B. Dubin–Johnson syndrome
C. Bile duct obstruction
D. Gilbert syndrome
Correct: C
Explanation: Obstructive jaundice → conjugated bilirubin can’t reach intestine → pale stool.
A 66-year-old develops colon cancer on the left side. What symptom is more typical of left-sided lesions?
A. Iron loss anemia
B. Obstructive symptoms and narrow stools
C. Occult GI bleeding
D. Massive diarrhea
Correct: B
Explanation: Left-sided tumors cause narrowed lumen → obstruction and "pencil-thin" stools.
A 22-year-old with appendicitis experiences pain migrating from periumbilical region to RLQ. What mechanism explains initial pain?
A. Somatic pain from peritoneum
B. Stretching of visceral peritoneum
C. Bacterial toxin release
D. Muscle spasm
Correct: B
Explanation: Early appendiceal inflammation irritates visceral peritoneum → vague periumbilical pain.
A 60-year-old alcoholic presents with spider angiomas, gynecomastia, and testicular atrophy. Mechanism?
A. Increased estrogen due to impaired liver metabolism
B. Excess progesterone
C. Renal failure
D. High cortisol
Correct: A
Explanation: Cirrhosis reduces estrogen clearance → hyperestrogenic signs.
A 54-year-old presents with dysphagia and halitosis. Barium swallow reveals outpouching above upper esophageal sphincter. Diagnosis?
A. Plummer–Vinson syndrome
B. Mallory–Weiss tear
C. Zenker diverticulum
D. Schatzki ring
Correct: C
Explanation: Zenker diverticulum = false diverticulum → regurgitation + bad breath.
A child with watery diarrhea improves with oral rehydration therapy containing glucose. Why?
A. Glucose inhibits secretion
B. Sodium–glucose cotransporter remains functional
C. Activates chloride channels
D. Decreases intestinal motility
Correct: B
Explanation: SGLT1 remains intact → glucose enhances Na⁺/water absorption even during diarrhea.
A 45-year-old has chronic GERD. Endoscopy shows squamous epithelium replaced by intestinal-type columnar cells. What is the clinical significance?
A. Risk of squamous cell carcinoma
B. Risk of adenocarcinoma
C. Reversible gastritis
D. Risk of hepatic failure
Correct: B
Explanation: Barrett esophagus → intestinal metaplasia → increased adenocarcinoma risk.
A 28-year-old presents with jaundice and pruritus. Labs: high conjugated bilirubin, normal AST/ALT. Which cause is most likely?
A. Hemolysis
B. Dubin–Johnson syndrome
C. Hepatitis B infection
D. Wilson disease
Correct: B
Explanation: Dubin–Johnson → conjugated hyperbilirubinemia without hepatocellular injury.
A patient with chronic pancreatitis develops diabetes mellitus. Which is the mechanism?
A. Insulin resistance
B. Destruction of pancreatic islet cells
C. Autoimmune attack on β-cells
D. Secondary hyperaldosteronism
Correct: B
Explanation: Chronic inflammation destroys islets → insulin deficiency → pancreatogenic diabetes.
A 6-year-old has chronic diarrhea, weight loss, and abdominal distension. Serology: anti-tTG IgA positive. Which is first-line therapy?
A. Lifelong gluten-free diet
B. Oral corticosteroids
C. Antibiotics
D. PPI therapy
Correct: A
Explanation: Celiac disease is treated with strict gluten exclusion.
A patient with acute pancreatitis develops hypocalcemia. What is the underlying mechanism?
A. Renal loss of calcium
B. Binding of calcium to saponified fat in necrotic tissue
C. Bone resorption defect
D. Vitamin D deficiency
Correct: B
Explanation: Fat necrosis binds Ca²⁺ → serum hypocalcemia in acute pancreatitis.
A 50-year-old with liver cirrhosis develops ascites. Which hemodynamic change contributes most?
A. Increased systemic vascular resistance
B. Portal hypertension → splanchnic vasodilation
C. Decreased aldosterone
D. Hyperkalemia
Correct: B
Explanation: Portal HTN → splanchnic vasodilation → renal sodium/water retention → ascites.
A patient presents with fever, RUQ pain, and jaundice. Ultrasound shows biliary obstruction. Which is likely diagnosis?
A. Acute cholecystitis
B. Acute cholangitis
C. Viral hepatitis
D. Pancreatic pseudocyst
Correct: B
Explanation: Charcot triad (Fever, RUQ pain, Jaundice) indicates ascending cholangitis.
A 65-year-old presents with painless rectal bleeding. Colonoscopy shows a cecal mass. Which symptom is most likely?
A. Iron-deficiency anemia
B. Obstruction
C. Melena only
D. Jaundice
Correct: A
Explanation: Right-sided colon cancers → occult blood loss → iron-deficiency anemia.
A patient presents with acute abdominal pain radiating to back, vomiting, and elevated amylase/lipase. Which is the most common cause in adults?
A. Gallstones
B. Alcohol
C. Hypertriglyceridemia
D. Trauma
Correct: A
Explanation: Gallstones are the most common cause of acute pancreatitis in adults, followed by alcohol.
A 30-year-old has diarrhea with mucus and blood, crampy abdominal pain. Colonoscopy shows continuous colonic involvement. Diagnosis?
A. Crohn disease
B. Ulcerative colitis
C. Infectious colitis
D. Celiac disease
Correct: B
Explanation: UC → continuous mucosal inflammation starting from rectum; Crohn is patchy.
A patient with chronic hepatitis B develops HCC. Which viral protein contributes to oncogenesis?
A. HBsAg
B. HBcAg
C. HBeAg
D. HBx protein
Correct: D
Explanation: HBx protein disrupts p53 → hepatocellular carcinoma development.
A 60-year-old has dysphagia for solids, weight loss, and odynophagia. Endoscopy shows exophytic tumor in mid-esophagus. Likely histology?
A. Adenocarcinoma
B. Squamous cell carcinoma
C. Small cell carcinoma
D. Neuroendocrine tumor
Correct: B
Explanation: Mid-esophagus → SCC; distal esophagus → adenocarcinoma, often Barrett-related.
A newborn fails to pass meconium within 48 hours. Rectal biopsy shows absence of ganglion cells. Diagnosis?
A. Pyloric stenosis
B. Hirschsprung disease
C. Meconium ileus
D. Duodenal atresia
Correct: B
Explanation: Aganglionic segment → functional obstruction → delayed meconium passage.
A 55-year-old alcoholic develops cirrhosis. Labs show AST>ALT. What is characteristic of alcoholic hepatitis?
A. AST:ALT <1
B. AST:ALT >2
C. ALT only elevated
D. Normal AST/ALT
Correct: B
Explanation: AST>ALT (usually >2) is classic in alcoholic hepatitis.
A patient presents with hematemesis after forceful vomiting. Endoscopy shows mucosal laceration at gastroesophageal junction. Diagnosis?
A. Boerhaave syndrome
B. Mallory–Weiss tear
C. Peptic ulcer
D. Esophageal varices
Correct: B
Explanation: Mallory–Weiss = longitudinal mucosal tear after retching; full-thickness = Boerhaave.
A patient with chronic cholestasis develops xanthomas. What is the underlying mechanism?
A. Increased LDL cholesterol due to bile excretion impairment
B. Decreased HDL production
C. Increased triglyceride production
D. Hemolysis
Correct: A
Explanation: Impaired bile excretion → cholesterol accumulation → xanthomas.
A 35-year-old presents with watery diarrhea after seafood ingestion. Likely mechanism?
A. Toxin-mediated activation of adenylate cyclase → ↑ cAMP
B. Direct invasion of colonic mucosa
C. Autoimmune enteropathy
D. Bile salt malabsorption
Correct: A
Explanation: Vibrio cholera → cholera toxin → cAMP-mediated Cl⁻ secretion → watery diarrhea.
A patient with Crohn disease develops strictures. Mechanism?
A. Transmural inflammation → fibrosis
B. Mucosal inflammation only
C. Muscularis atrophy
D. Villous blunting
Correct: A
Explanation: Crohn = transmural inflammation → fibrosis → strictures and fistulas.
A patient with H. pylori develops peptic ulcer. Which enzyme/protein contributes to mucosal damage?
A. Urease
B. Lactase
C. Pepsin inhibitor
D. Trypsin
Correct: A
Explanation: H. pylori urease → ammonia production → mucosal injury → ulcer formation.
A patient presents with painless jaundice and palpable gallbladder. Which condition is classic?
A. Choledocholithiasis
B. Pancreatic head carcinoma (Courvoisier sign)
C. Hepatitis A
D. Gilbert syndrome
Correct: B
Explanation: Courvoisier sign = non-tender, palpable gallbladder in pancreatic head obstruction.
A patient presents with chronic diarrhea, bloating, and iron deficiency anemia. Duodenal biopsy shows villous atrophy. Which nutrient deficiency is most likely?
A. Vitamin B12
B. Folate
C. Vitamin D
D. Iron
Correct: D
Explanation: Celiac disease → malabsorption, particularly of iron in proximal small intestine → iron-deficiency anemia.
A 45-year-old alcoholic develops acute pancreatitis. Which lab abnormality is classic?
A. Hypernatremia
B. Hypocalcemia
C. Hyperkalemia
D. Hypoglycemia
Correct: B
Explanation: Fat necrosis binds calcium → hypocalcemia; often seen in acute pancreatitis.
A patient presents with dysphagia to solids and liquids, regurgitation, and chest pain. Barium swallow shows “bird-beak” appearance. Which test confirms the diagnosis?
A. Endoscopy
B. Esophageal manometry
C. Abdominal ultrasound
D. CT scan
Correct: B
Explanation: Achalasia → loss of inhibitory neurons → manometry confirms aperistalsis and LES failure.
A patient with UC develops fever, abdominal distension, and hypotension. X-ray shows colonic dilation. Likely complication?
A. Toxic megacolon
B. Ileus
C. Small bowel obstruction
D. Perforated appendicitis
Correct: A
Explanation: UC → severe inflammation → colonic dilation → risk of perforation.
A patient develops jaundice, dark urine, and pale stools. Labs: conjugated hyperbilirubinemia. Most likely cause?
A. Hemolysis
B. Obstructive jaundice
C. Gilbert syndrome
D. Hemochromatosis
Correct: B
Explanation: Conjugated bilirubin cannot reach intestine → dark urine (renal excretion) and pale stools.
A patient with gallstones presents with fever, RUQ pain, and jaundice. Diagnosis?
A. Acute cholecystitis
B. Ascending cholangitis
C. Hepatitis A
D. Pancreatic pseudocyst
Correct: B
Explanation: Charcot triad indicates ascending cholangitis due to bile duct obstruction.
A patient has painless bleeding per rectum. Colonoscopy reveals angiodysplasia in the cecum. Which condition is commonly associated?
A. Diabetes mellitus
B. Chronic kidney disease
C. Hyperthyroidism
D. COPD
Correct: B
Explanation: CKD → vascular malformations → increased risk of angiodysplasia bleeding.
A patient with chronic hepatitis B develops hepatocellular carcinoma. Which viral protein is oncogenic?
A. HBsAg
B. HBcAg
C. HBeAg
D. HBx protein
Correct: D
Explanation: HBx protein interferes with p53 → increases HCC risk.
A patient presents with jaundice and pruritus. Labs: ALP elevated, mildly increased AST/ALT. Likely diagnosis?
A. Primary sclerosing cholangitis
B. Hepatitis A
C. Wilson disease
D. Hemochromatosis
Correct: A
Explanation: PSC → chronic cholestasis → ALP elevated more than AST/ALT.
A 55-year-old develops right-sided colon cancer. Which clinical presentation is most typical?
A. Iron-deficiency anemia
B. Obstructive symptoms
C. Hematochezia only
D. Ascites
Correct: A
Explanation: Right-sided lesions → bleeding → chronic anemia; left-sided → obstruction.
A 60-year-old smoker develops progressive dysphagia and weight loss. Biopsy shows squamous cell carcinoma mid-esophagus. Risk factors?
A. Smoking and alcohol
B. Barrett esophagus
C. GERD
D. Celiac disease
Correct: A
Explanation: SCC of mid-esophagus strongly associated with smoking + alcohol; Barrett → adenocarcinoma.
A patient with chronic pancreatitis develops steatorrhea. Which enzyme deficiency is responsible?
A. Amylase
B. Lipase
C. Trypsin
D. Chymotrypsin
Correct: B
Explanation: Lipase deficiency → fat malabsorption → steatorrhea in chronic pancreatitis.
A patient presents with upper GI bleeding. Endoscopy shows a longitudinal mucosal tear at gastroesophageal junction. Diagnosis?
A. Boerhaave syndrome
B. Mallory–Weiss tear
C. Peptic ulcer
D. Esophageal varices
Correct: B
Explanation: Mallory–Weiss tear = partial mucosal tear after retching; Boerhaave = full-thickness tear.
A patient develops painless jaundice with palpable gallbladder. Which disease is classically associated?
A. Choledocholithiasis
B. Pancreatic head carcinoma
C. Hepatitis A
D. Gilbert syndrome
Correct: B
Explanation: Courvoisier sign → non-tender, palpable gallbladder with pancreatic head obstruction.
A 70-year-old with cirrhosis develops confusion and asterixis. Precipitating factor?
A. Protein load
B. Hypokalemia
C. Hypernatremia
D. Hypocalcemia
Correct: A
Explanation: Increased nitrogen load → ammonia accumulation → hepatic encephalopathy.
A patient with celiac disease has persistent diarrhea and malabsorption despite a gluten-free diet. Which deficiency is common?
A. Vitamin B12
B. Iron
C. Vitamin C
D. Calcium
Correct: A
Explanation: Chronic small intestinal damage → B12 deficiency (distal small intestine involvement).
A patient presents with pruritus and hyperbilirubinemia. ALP > ALT/AST. Which lab abnormality often develops?
A. Hypercholesterolemia
B. Hypocholesterolemia
C. Hypertriglyceridemia
D. Hypokalemia
Correct: A
Explanation: Chronic cholestasis → impaired bile excretion → cholesterol accumulation → xanthomas.
A patient develops watery diarrhea after contaminated seafood. Mechanism?
A. Increased cAMP → Cl⁻ secretion
B. Direct invasion of colonic mucosa
C. Autoimmune injury
D. Bile salt malabsorption
Correct: A
Explanation: Vibrio cholera → cholera toxin → adenylate cyclase activation → massive water/Cl⁻ secretion.
A patient with Crohn disease develops fistulas. Mechanism?
A. Transmural inflammation
B. Mucosal inflammation only
C. Villous blunting
D. Smooth muscle atrophy
Correct: A
Explanation: Crohn disease → transmural inflammation → fistula and stricture formation.
A patient with H. pylori infection develops peptic ulcer. Which bacterial factor contributes most to mucosal injury?
A. Urease
B. Lactase
C. Pepsin inhibitor
D. Trypsin
Correct: A
Explanation: Urease converts urea → ammonia → local mucosal damage → ulcers.
A newborn has nonbilious projectile vomiting and palpable olive mass in the abdomen. Labs: hypochloremic metabolic alkalosis. Diagnosis?
A. Pyloric stenosis
B. Duodenal atresia
C. Hirschsprung disease
D. Meconium ileus
Correct: A
Explanation: Hypertrophic pylorus → gastric outlet obstruction → electrolyte disturbances.
A patient presents with left-sided colon cancer. Common symptom?
A. Obstruction and narrow stools
B. Iron deficiency anemia
C. Occult bleeding only
D. Steatorrhea
Correct: A
Explanation: Left-sided tumors → reduced lumen → constipation and pencil-thin stools.
A patient has cirrhosis with spider angiomas, gynecomastia, and testicular atrophy. Mechanism?
A. Hyperestrogenism due to impaired liver metabolism
B. Hyperaldosteronism
C. Hyperprogesteronemia
D. Hypocortisolism
Correct: A
Explanation: Impaired estrogen metabolism in cirrhosis → feminization signs.
A patient develops chronic diarrhea and fat-soluble vitamin deficiencies after jejunal resection. Mechanism?
A. Bile acid malabsorption
B. Insufficient gastric acid
C. Rapid motility
D. Pancreatic enzyme deficiency
Correct: A
Explanation: Ileal/jejunal resection → decreased bile salt pool → fat malabsorption.
A patient presents with painless rectal bleeding and cecal mass. What is typical?
A. Iron-deficiency anemia
B. Obstructive symptoms
C. Ascites
D. Jaundice
Correct: A
Explanation: Right-sided colon cancers → occult bleeding → chronic anemia.
A patient with chronic hepatitis C has elevated ALT>AST. What lesion is earliest?
A. Macrovesicular steatosis
B. Microvesicular steatosis
C. Fibrosis
D. Cirrhosis
Correct: A
Explanation: Hepatic fat accumulation precedes fibrosis in chronic viral hepatitis.
A 6-year-old with intussusception has currant-jelly stool. Which is typical lead point?
A. Hypertrophied Peyer patches
B. Meckel diverticulum
C. Lipoma
D. Lymphoma
Correct: A
Explanation: Enlarged Peyer patches → common lead point in pediatric intussusception.
A patient presents with epigastric pain radiating to back, elevated serum lipase. Most common cause in adults?
A. Gallstones
B. Alcohol
C. Hypertriglyceridemia
D. Trauma
Correct: A
Explanation: Gallstones are the most frequent cause of acute pancreatitis in adults.
A patient with UC develops severe abdominal distension. Radiograph shows colonic dilation. Immediate concern?
A. Toxic megacolon
B. Ileus
C. Small bowel obstruction
D. Appendicitis
Correct: A
Explanation: Toxic megacolon → risk of perforation, requires urgent management.
A 40-year-old with chronic HCV infection develops hepatocellular carcinoma. Which histologic feature is common?
A. Fibrous septa with regenerative nodules
B. Steatosis
C. Lipid-laden Kupffer cells
D. Bile duct hyperplasia
Correct: A
Explanation: Cirrhosis precedes HCC; fibrous septa and nodules are characteristic.