Hamartomatous colonic polyps

Hamartomas are benign tumors composed of normal tissue components present in disorganized overgrowth. Hamartomatous colonic polyps are found in hereditary polyposis syndromes characterized by multiple polyps and increased cancer risk. Major syndromes: (1) Peutz-Jeghers syndrome (PJS)—autosomal dominant STK11 mutation; presents with characteristic mucocutaneous pigmentation (dark macules on lips, buccal mucosa, hands), multiple GI hamartomas (primarily jejunal but also stomach, colon), bleeding, obstruction, and markedly increased cancer risk (colorectal, gastric, pancreatic, breast, ovarian); (2) Juvenile polyposis syndrome—autosomal dominant SMAD/BMPR1A mutations; presents with multiple juvenile polyps (typically solitary hamartomas with cystic spaces, not true adenomas) in colon/GI tract, bleeding, anemia, and increased colorectal cancer risk (~40%); (3) Cowden syndrome (PTEN hamartoma tumor syndrome)—autosomal dominant PTEN mutation; presents with mucocutaneous findings (trichilemmomas, papules, keratoses), GI polyps (primarily hamartomatous), and increased breast, thyroid, and colorectal cancer risk; (4) Cronkhite-Canada syndrome (rare, acquired)—polyposis with ectodermal features (alopecia, nail dystrophy, skin hyperpigmentation). Pathophysiology: germline mutations in tumor suppressor genes (STK11, SMAD, PTEN) predispose to polyp formation; hamartomas have low malignant potential themselves but existence of syndrome indicates genetic predisposition to malignancy. Diagnosis: endoscopic findings of polyps + genetic testing + family history. Complications: bleeding (anemia), intussusception/obstruction (small bowel JPS), perforation. Management: screening endoscopy (polyp surveillance, removal of large polyps > 1.5 cm), genetic counseling, cancer screening (colonoscopy, upper endoscopy, EGD—recommendations vary by syndrome). Malignant potential: JPS and PJS have significant colorectal cancer risk; in PJS, cancer risk extends beyond colon. On boards: link hereditary polyposis syndromes to cancer predisposition and recognize syndromic features (PJS pigmentation, Cowden trichilemmomas).