SMAD4 juvenile polyposis syndrome and hereditary haemorrhagic telangiectasia presenting in a middle-aged man as a large fungating gastric mass, polyposis in both upper and lower GI tract and iron deficiency anaemia, with no known family history.

Juvenile polyposis syndrome (JPS) and hereditary haemorrhagic telangiectasia (HHT) are rare autosomal dominant diseases, where symptoms manifest at childhood. A 32-year-old man with no family history of JPS or HHT with SMAD4 gene mutation who developed signs and symptoms only at the age of 32, when he was an adult. In this article, we highlight the steps taken to diagnose this rare pathology, explain its pathophysiology and management.