Extra-abdominal desmoid tumour. Report of three cases.

Three cases of desmoid tumour in a lower extremity are described. Primary radical excision is necessary for this type of tumour, because of its clear tendency to recur. In the described cases surgery was complicated by the proximity of neural structures and blood vessels. Preoperative angiography was useful for determining the size of the tumour and its position in relation to large blood vessels. Pathologic vascularity was found in the tumours, but histologic examination revealed no sign of malignancy. The histologic structure of the tumours corresponded in all respects to benign fibromatosis, apart from a clear increase in the number of mast cells. The tumours showed a tendency to grow between the muscle fibres, though a pseudocapsule was observed at operation in two cases. None of the specimens from the extirpation line displayed any signs of tumour tissue, but this did not preclude recurrence.