Case ReportA case report of desmoid tumour-a forgotten aspect of FAP?

- Desmoid tumours are the second commonest tumour in FAP after colonic adenomas.
- Desmoid tumours do not metastasise but are locally aggressive.
- Patients with FAP should be examined regularly post-panproctocolectomy since desmoid tumours may arise.

IntroductionDesmoid tumours are locally aggressive tumours which are common in Familial Adenomatous Polyposis (FAP).Presentation of caseA 20-year old Familial Adenomatous Polyposis (FAP) patient presented with abdominal pain and distention. Abdominal imaging showed small bowel obstruction and hydronephrosis due to a pelvic mass. This mass showed significant enlargement on repeat imaging, and a diagnostic biopsy confirmed desmoid tumour.The mass was deemed unresectable and he was initially started on sulindac and raloxifene. Repeat imaging however showed further enlargement of the tumour, and therefore vinblastine + methotrexate chemotherapy was commenced, with a good response.DiscussionFAP is an autosomal dominant condition caused by a germline mutation in the adenomatous polyposis coli (APC) gene. Gardner's syndrome is also caused by a mutation in the APC gene, and is now considered a different phenotypic presentation of FAP. Desmoid tumours are initially kept under observation while their size remains stable. Treatment options for enlarging desmoids tumours include surgery (first-line), radiotherapy, and systemic therapy with non-cytotoxic and cytotoxic therapy.ConclusionFAP patients should be examined regularly post-panprocotocolectomy, since desmoid tumours may arise. The presence of epidermal cysts in this FAP patient suggests a diagnosis of Gardner's syndrome.