Abdominal desmoid masses in Gardner's syndrome.

Abdominal masses, "desmoid tumors," occur in approximately 4% of patients with Gardner's Syndrome, usually 1--3 years after total colectomy. Histologic sections usually resemble those of an infiltrating fibrous tumour, a desmoid lesion. The radiographic pattern may be similar to any diffuse abdominal retroperitoneal tumor, metastatic disease, lymphoma, or possibly retractile mesenteritis. The clinical setting usually differentiates these entities.