A 52-year-old man from rural Maharashtra presents with a 3-week history of progressive jaundice, pale stools, and dark urine. He reports no fever, abdominal pain, or weight loss. On examination, he is afebrile, has mild hepatomegaly, and no splenomegaly. Laboratory investigations show: total bilirubin 8.2 mg/dL (direct 6.8 mg/dL), AST 65 U/L, ALT 58 U/L, ALP 280 U/L, albumin 3.8 g/dL. Abdominal ultrasound reveals dilated intrahepatic and extrahepatic bile ducts with a 2.5 cm hypoechoic lesion at the head of pancreas. What is the most likely diagnosis?

Explanation

## Clinical Analysis ### Key Features Supporting Pancreatic Adenocarcinoma **Key Point:** The triad of progressive jaundice, pale stools (acholia), and a pancreatic head mass on imaging is pathognomonic for pancreatic cancer causing obstructive jaundice. **Clinical Pearl:** Painless jaundice with a palpable pancreatic mass is a classic presentation of pancreatic head carcinoma. The absence of acute pain distinguishes this from acute pancreatitis. ### Laboratory Pattern Analysis | Parameter | Finding | Interpretation | |-----------|---------|----------------| | Bilirubin (direct > indirect) | 6.8/8.2 (83% direct) | Obstructive pattern | | ALP (markedly elevated) | 280 U/L | Biliary obstruction | | Transaminases (mild elevation) | AST 65, ALT 58 | Cholestasis > hepatocellular | | Albumin (preserved) | 3.8 g/dL | No hepatic synthetic dysfunction | **High-Yield:** In obstructive jaundice, ALP rises disproportionately to transaminases. Direct hyperbilirubinemia >80% confirms extrahepatic obstruction. ### Imaging Findings 1. **Dilated intrahepatic bile ducts** — upstream obstruction 2. **Dilated extrahepatic bile duct** — confirms obstruction distal to confluence 3. **Hypoechoic lesion at pancreatic head** — mass effect causing duct compression **Mnemonic:** **CHOPS** = Courvoisier gallbladder, Hepatomegaly, Obstruction (painless), Pancreatic mass, Steatorrhea — classic pancreatic cancer presentation. ### Differential Exclusion ```mermaid flowchart TD A[Painless jaundice + Pancreatic mass]:::outcome --> B{Acute pain?}:::decision B -->|Yes| C[Acute pancreatitis]:::outcome B -->|No| D{Fever + cholangitis signs?}:::decision D -->|Yes| E[Choledocholithiasis]:::outcome D -->|No| F{Chronic liver disease?}:::decision F -->|Yes| G[PBC/PSC]:::outcome F -->|No| H[Pancreatic cancer]:::action ``` **Clinical Pearl:** Courvoisier's law states that in the presence of jaundice, a palpable gallbladder suggests malignancy (pancreatic or biliary), not stones (which cause fibrosis and contraction). ### Why This Patient Has Pancreatic Cancer 1. **Progressive, painless jaundice** — classic red flag 2. **Pancreatic head mass on imaging** — direct evidence 3. **Obstructive biochemistry** — confirms biliary obstruction 4. **No acute inflammation markers** — rules out pancreatitis 5. **Preserved synthetic function** — no cirrhosis or acute hepatitis [cite:Harrison 21e Ch 297]