Retroperitoneal malignant fibrous histiocytoma without histological atypias

A case of a 36-year-old woman suspected of hepatic hydatid cyst with dyseptic symptoms, hepatomegalia, profound pains in the right hypochondrium is presented. During the operation a 15/12/17 cm well-incapsulated tumour is extirpated. The tumour stretched from the upper right renal pole behind the right hepatic lobe as far as the diaphragm and while sectioning it was grey and orange. Histopathologically we found a fibrous histiocytoma with zones of storiform fascicular pattern alternating with areas of histocytic cells with vacuolar-foamy cytoplasm, rich in lipids and without atypias or mitoses. We report the frequency, histological aspects of the fibrous histiocytomas as well as some particularities of their retroperitoneal location.