skip to main content

Juvenile Polyposis Syndrome — ESEGH MCQ

Instant feedback + full explanation. One question, done properly.

HardColorectalJuvenile Polyposis SyndromeESEGH

A 15-year-old boy undergoes colonoscopy for recurrent rectal bleeding and iron-deficiency anaemia. Eight colorectal polyps are removed; histology shows cystically dilated mucus-filled glands within an oedematous, inflamed lamina propria. His father has required repeated endoscopic removal of similar polyps and is under specialist follow-up for recurrent epistaxis and pulmonary arteriovenous malformations. Which diagnosis and germline pathogenic variant best explain this family?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — Juvenile polyposis syndrome; SMAD4 pathogenic variant

This is juvenile polyposis syndrome (JPS), with the family’s hereditary haemorrhagic telangiectasia phenotype indicating a SMAD4 pathogenic variant. The number of histologically characteristic juvenile polyps and the affected first-degree relative independently satisfy clinical criteria for JPS. JPS may result from SMAD4 or BMPR1A variants, but pulmonary arteriovenous malformations and recurrent epistaxis specifically favour SMAD4-associated JPS–HHT overlap. Peutz–Jeghers polyps have arborising smooth-muscle cores and are associated with mucocutaneous pigmentation. Cowden syndrome usually features macrocephaly and characteristic mucocutaneous lesions. FAP produces numerous adenomatous rather than juvenile hamartomatous polyps, while Lynch syndrome predisposes to colorectal cancer without a juvenile polyposis phenotype.

Reference: Monahan KJ et al. BSG/ACPGBI/UKCGG guidelines for the management of hereditary colorectal cancer, section “Juvenile polyposis syndrome”, 2020. https://www.bsg.org.uk/BSG/media/BSG-Media/Guidelines-for-the-management-of-hereditary-colorectal-cancer-full_.pdf