Solitary fibrous tumour of the kidney

Solitary fibrous tumours are relatively rare neoplasms initially described in the pleura. Such lesions are now reported in many extrathoracic sites. To our knowledge, only 8 cases have been reported in the kidney. All these cases were benign. We report a patient with a solitary fibrous tumour of the kidney with infiltration of the wall of the renal vein. Microscopic examination showed proliferation of spindle cells with a prominent vascular haemangiopericytoma-like pattern. Hypercellular areas were admixed with hyalinized collagenous zones. The neoplastic cells stained for vimentin and CD34. CD31 was negative. Biologically, we did not find any arguments for malignancy: the flow cytometric study showed diploid histograms, and immunostaining for p53 was negative.