Desmoid tumor of mesentery in familial adenomatous polyposis: a case report

Large desmoid tumour of the small bowel mesentery

A 74-year-old man was being investigated for a pancreatic insulinoma when an incidental mesenteric mass measuring 2.6 cm x 2.5 cm was noticed on CT imaging. A wait-and-see approach was decided on. Thirty-nine months later, the patient presented with symptoms of abdominal obstruction. CT images revealed the mesenteric mass filled majority of the abdominal cavity and measured 29 cm x 26 cm x 16 cm. The patient underwent an open bypass gastrojejunostomy which stopped working a few weeks later due to further compression by the tumour. A debulking surgery was performed: a right hemicolectomy and small bowel resection with excision of the desmoid tumour and bypass gastrojejunostomy. The tumour measured 12.6 kg and was macroscopically visualised to have a white cut surface with a focal translucent area. Microscopic analysis revealed bland spindle cells with pale eosinophilic cytoplasm showing no cytological atypia, in keeping with a mesenteric desmoid tumour. Currently, two and a half years from the debulking surgery, the patient remains well and in remission with planned surveillance.

Large desmoid tumors in familial adenomatous polyposis: a successful outcome

Desmoid tumors develop from connective tissue, fasciae, and aponeuroses, and may occur in the context of familial adenomatous polyposis or may arise sporadically; also, they may be extra-abdominal, intra-abdominal, or located in the abdominal wall. These benign tumors have a great aggressiveness with a high rate of local recurrence. Familial adenomatous polyposis is an inherited condition with autosomal dominant transmission, and is characterized by the development of multiple colonic and rectal adenomatous polyps, as well as desmoid tumors. We present the case of a 54-year-old woman with germline APC gene mutation, who underwent a total colectomy, subsequently developing two large infiltrative solid intra-abdominal lesions consistent with desmoid tumors. Medical treatment with Cox-2 inhibitors was initiated without result. She was submitted to resection for intestinal obstruction, but developed local recurrence. The lesions were also unresponsive to tamoxifen, and chemotherapy was initiated with dacarbazine plus doxorubicin, switching to vinorelbine plus methotrexate, achieving a good response in all lesions after 12 months. The approach to these intra-abdominal lesions should be progressive, beginning with observation, then a medical approach with non-steroidal anti-inflammatory drugs or with an anti-hormonal agent. Afterwards, if progression is still evident, chemotherapy should be started. Surgery should be reserved for resistance to medical treatment, in palliative situations, or for extra-abdominal or abdominal wall desmoids tumors.