DESMOID TUMORS IN FAMILIAL ADENOMATOUS POLYPOSIS

Desmoids are rare, benign fibromatous lesions, which can arise in pati ents with familial adenomatous polyposis (FAP), a disorder caused by g ermline adenomatous polyposis coli (APC) gene mutation. This study inv estigated the risk of desmoids in FAP, the relation between specific A PC gene mutations and desmoid formation, and the clinical characterist ics of FAP patients with desmoids. Eighty three of 825 FAP patients (1 0%) from 49 of 161 kindreds (30%) had desmoids. The absolute risk of d esmoids in FA.P patients was 2.56/1000 person years; comparative risk was 852 times the general population. APC gene mutations were similar in families with and without desmoids. The female/male ratio was 1.4 ( p=NS). Previous abdominal surgery was noted in 68% of patients with ab dominal desmoids (55% developed within five years postoperatively). De smoid risk in FAP family members of a desmoid patient was 25% in first degree relatives v 8% in third degree relatives. Desmoids are a compa ratively common complication of FAP associated with surgical trauma an d familial aggregation. Desmoid development was not linked to specific APC gene mutations and was not found predominantly in women. Studies of chemopreventive therapy, given within five years after abdominal su rgery, should be considered in FAP patients with a family history of d esmoid disease.