A 9-year-old boy has hyperpigmented macules clustered around the lips, buccal mucosa, fingertips and toes since early childhood. He has recurrent colicky abdominal pain. Barium studies reveal multiple polyps in the small intestine. Biopsy of a polyp would show:

• A Adenomatous polyp with high-grade dysplasia
• B Inflammatory fibroid polyp with eosinophilic infiltrate
• C Juvenile polyp with cystically dilated glands
• D Hamartomatous polyp with arborising smooth muscle ✓

Explanation

Peutz-Jeghers syndrome features mucocutaneous melanotic macules plus gastrointestinal hamartomatous polyps whose hallmark is an arborising network of smooth muscle extending into the lamina propria. It is caused by STK11 (LKB1) germline mutations. The main clinical danger is intussusception, and carriers have increased cancer risk of pancreas, breast, ovary and colon. Juvenile polyps lack the arborising muscle and occur in juvenile polyposis instead.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.