Solitary fibrous tumour of transverse mesocolon: an unusual location.

Abstract

Solitary fibrous tumours are rare spindle cell mesenchymal neoplasms, most develop in the pleura. It has been described at unusual sites including orbit, peritoneum, mediastinum, lung, liver and spinal nerve rootlets. Its occurrence in mesentery is exceptionally rare. We describe here a case of SFT originating in transverse mesocolon. A 55 year old woman presented with a painless abdominal mass which was discovered on routine examination. At laparotomy, the mass was found to arise from the transverse mesocolon. It was globoid, solid, firm, 170 mm in diameter with a heterogeneous yellow-tan cut surface. It was easily shelled out without a surface breach. Histology showed an encapsulated, compact, spindle cell tumour with a bland nuclear morphology. Immunohistochemistry showed strong CD34 and betacatenin positivity of the spindle cells. It was also positive for CD99 and bcl2 and negative for CD117, s100, smooth muscle actin and epithelial markers, thus favouring this to be a solitary fibrous tumour. To our knowledge only one previous case of SFT in mesocolon has been described in the literature. Prognosis of SFT is excellent in benign type with a very low recurrence rate. It is much more guarded in the malignant variety which has a very high recurrence rate with chance of metastasis.