Haemangiopericytoma of the sigmoid mesentery.

Haemangiopericytoma is a rare, vascular soft tissue tumour originating from the pericytes surrounding capillaries. We report a case of haemangiopericytoma in the sigmoid mesocolon and are aware of only one previously case. A 61-year-old man was referred with a left iliac fossa mass. At operation, a 10-cm diameter mass was found to be arising from the sigmoid mesentery (Fig. 1). The mass did not involve the bowel wall and there was no clinical evidence of metastatic disease. A sigmoid colectomy with primary anastomosis was performed. The patient made an uneventful recovery. Pathological assessment of the specimen revealed a 95 x 70 x 50 mm(3), purple, lobulated mass within the sigmoid mesocolon adjacent to the bowel. Immunohistological analysis (positive CD34, focal factor VIII) was consistent with a diagnosis of a haemangiopericytoma. Complete excision with adequate margins remains the treatment of choice. We therefore suggest that patients be carefully followed for long periods and advised of the risk of long-term relapse.