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.