Primary malignant fibrous histiocytoma of the abdominal cavity: CT findings and pathological correlation

AIM: To study computed tomography (CT) features of abdominal malignant fibrous histiocytoma (MFH) in various rare locations. METHODS: We retroprospectively identified cases of MFH involving the abdominal cavity. Particular attention was paid to details regarding imaging features and histological types. RESULTS: The study population consisted of seven men and one woman, with a mean age of 52.5 years. Seven patients had some physical symptoms, while one was incidentally detected. The sites of origin were liver (n = 3), greater omentum (n = 1), superior mesentery (n = 1), ileum (n = 1), right psoas muscle (n = 1) and right kidney (n = 1). With the exception of the ileum lesion, all were of huge size. The contour of the lesions was more or less clear. Foci of necrosis were present in six lesions (n = 6). On plain CT scan, all lesions were hypo to iso dense. The lesion in the greater omentum was cystic. One lesion (n = 1) showed significant enhancement and the cystic lesion showed mild peripheral enhancement. An abundance of blood vessels surrounding the mass was seen in two lesions (n = 2) and both were of the inflammatory variety. Pathological examination revealed storiform-pleomorphic variety (n = 4), inflammatory variety (n = 3) and myxoid variety (n = 1). Two of the patients with inflammatory MFH had a clinical presentation of fever and one was afebrile, however, blood investigations in all three showed leukocytosis. CONCLUSION: Primary MFHs of the abdominal viscera and gastrointestinal tract are generally huge soft tissue masses containing areas of low attenuation and mild to moderate contrast enhancement.