A 52-year-old man from rural Maharashtra presents with a 3-week history of progressive jaundice, dark urine, and pale stools. He reports no fever, abdominal pain, or weight loss. On examination, he is afebrile with scleral icterus and hepatomegaly (3 cm below costal margin). Abdominal examination reveals no tenderness or ascites. Laboratory investigations show: total bilirubin 8.2 mg/dL (conjugated 6.8 mg/dL), AST 78 U/L, ALT 82 U/L, ALP 340 U/L, albumin 3.8 g/dL. Abdominal ultrasound demonstrates dilated intrahepatic and extrahepatic bile ducts with a hypoechoic lesion at the head of pancreas measuring 2.8 cm. What is the most likely diagnosis?

Explanation

## Clinical Reasoning **Key Point:** The combination of painless progressive jaundice, pale stools, dark urine, and imaging evidence of dilated bile ducts with a pancreatic head mass is pathognomonic for obstructive jaundice due to pancreatic cancer. ### Pattern Recognition This case presents the classic **Courvoisier–Terrier sign** — a palpable, non-tender gallbladder in the setting of jaundice and a pancreatic head lesion. The clinical triad of painless jaundice, weight loss (implied by pale stools and dark urine), and a pancreatic mass defines pancreatic adenocarcinoma until proven otherwise. ### Laboratory Interpretation | Finding | Interpretation | |---------|----------------| | Conjugated hyperbilirubinemia (6.8/8.2) | Biliary obstruction | | ALP 340 U/L (markedly elevated) | Cholestasis; ALP > ALT/AST ratio | | Mild transaminitis (AST/ALT ~80) | Obstruction, not hepatocellular injury | | Normal albumin | Preserved synthetic function | **High-Yield:** In obstructive jaundice, **ALP rises disproportionately to transaminases**. The ALP:ALT ratio here is ~4:1, typical of biliary obstruction. ### Imaging Findings - **Dilated intrahepatic and extrahepatic bile ducts** = obstruction distal to the common hepatic duct - **Hypoechoic lesion at pancreatic head** = mass effect causing ductal compression - **No ascites or portal hypertension signs** = rules out cirrhosis **Clinical Pearl:** Painless jaundice in an older patient with a pancreatic head mass on imaging is pancreatic cancer until proven otherwise. Pain is actually a late feature. ### Why This Diagnosis Fits 1. **Age and geography:** Pancreatic cancer peaks in the 6th–7th decade; rural India has endemic risk factors. 2. **Painless onset:** Early pancreatic head tumors obstruct the bile duct before causing pain. 3. **Imaging:** Direct visualization of a pancreatic mass with ductal dilation is diagnostic. 4. **Laboratory pattern:** Obstructive (conjugated) hyperbilirubinemia with cholestatic enzyme elevation. **Mnemonic:** **PANCREAS** — **P**ainless jaundice, **A**lkaline phosphatase elevated, **N**o tenderness, **C**ourvoisier sign, **R**ural/risk factors, **E**xtrahepatic obstruction, **A**denoma (pancreatic), **S**onographic mass.