Pancreatic ductal adenocarcinoma most frequently arises in which part of the pancreas, and what percentage of cases carry KRAS mutations?

• A Body/tail; ~30% KRAS mutations
• B Head; ~50% KRAS mutations
• C Body/tail; ~75% KRAS mutations
• D Head; ~95% KRAS mutations ✓

Explanation

Approximately 60–70% of pancreatic ductal adenocarcinomas arise in the head of the pancreas, where they typically obstruct the common bile duct causing jaundice. KRAS mutation (predominantly codon 12) is the most frequent molecular event, present in ~95% of cases, and is among the earliest genetic changes. Progression involves sequential acquisition of CDKN2A, TP53, and SMAD4 mutations.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.