[Malignant fibrous histiocytoma of the penis]

According to the most recent World Health Organization (WHO) guidelines a diagnosis of malignant fibrous histiocytoma (MFH) should be made only for lesions composed of tumor cells without evidence of a specific line of differentiation. This is therefore a diagnosis by exclusion which is why the name of undifferentiated high-grade pleomorphic sarcoma (UPS) should be preferred. Soft tissue sarcomas currently have an incidence in all body regions of approximately 20 cases per 1 million inhabitants per year. Soft tissue tumors of the penis represent approximately 5 % of all penile tumors and the incidence of penile sarcomas is estimated to be approximately 0.6-1 case per 100,000 patients. Only seven cases have so far been reported in the literature. This article describes the case of a 61-year-old Caucasian male who presented with a painless mass sited in the upper part of the corpus cavernosa. An incisional biopsy with a subsequent investigation using an extensive immunohistochemical panel were performed and a high-grade undifferentiated pleomorphic sarcoma or pleomorphic storiform MFH was diagnosed. In addition to the case report a literature review is presented to elaborate the discussion on the differential diagnoses of these kinds of lesions.