Pleomorphic malignant fibrous histiocytoma (MFH), also known as undifferentiated high-grade pleomorphic sarcoma according to the latest World Health Organization classification, is a diagnosis of exclusion and extremely rare in adult scrotal/paratesticular region. Clinical presentation of scrotal/paratesticular pleomorphic MFH is usually a painless and gradual scrotal swelling. We report a case of scrotal MFH in a 63-year-old man who presented as Fournier gangrene after 10-month painful scrotal swelling and multiple procedures. The specimen of emergent debridement was submitted for pathologic and bacteriologic examination. Microscopically, the lesion had marked architectural and cytologic pleomorphism. The neoplastic cells were positive for vimentin, but negative for all lineage-specific markers. Fluorescence in-situ hybridization showed an aneuploid karyotype and negative results for lipomatous tumor abnormalities. Bacterial cultures of the specimen showed extensive growth of virulent polymicrobes. The diagnosis of scrotal/paratesticular pleomorphic MFH with concurrent Fournier gangrene was made. Thoracic computed tomography scan showed bilateral multiple pulmonary nodules. The patient died 1 month later.