Desmoids are rare, benign fibromatous lesions, which can arise in patients with
familial adenomatous polyposis (FAP), a disorder caused by germline
adenomatous polyposis coli (APC) gene mutation. This study investigated the risk of
desmoids in FAP, the relation between specific APC gene mutations and
desmoid formation, and the clinical characteristics of FAP patients with
desmoids. Eighty three of 825 FAP patients (10%) from 49 of 161 kindreds (30%) had
desmoids. The absolute risk of
desmoids in FAP 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 abdominal
desmoids (55% developed within five years postoperatively).
Desmoid risk in FAP family members of a
desmoid patient was 25% in first degree relatives v 8% in third degree relatives.
Desmoids are a comparatively common complication of FAP associated with surgical
trauma and 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 surgery, should be considered in FAP patients with a family history of
desmoid disease.