A Case of Cutaneous Fusariosis of the Scrotum as a Complication of Acute Myeloid Leukemia.
Fusarium, a hyphomyocetous fungus, is often isolated from the environment as a laboratory contaminant, but is also known as a pathogen causing keratomycosis, onychomycosis, and opportunistic infection of the skin and viscera. We report a 67-year-old man with localized cutaneous fusariosis of the scrotum, as a complication of acute myeloid leukemia (AML) under chemotherapy. An induration of 25 mm in diameter, which was covered by necrosis and black crust and with pain upon pressure, was found on the scrotum. Direct microscopic examination of the necrosis showed numerous fungal elements. Culture on Sabouraud dextrose agar with cycloheximide yielded a floccose, grayish white colony. Microscopically, crescent-shaped macroconidia and oval microconidia were abundant. The fungus was identified using gene analysis as Fusarium falciforme of the Fusarium solani species complex. The lesion was treated by voriconazole (total dose: 66,180 mg) and was reduced to 15 mm in diameter. Other metastatic lesions did not appear. After 4 months from the first visit to our department, the patient died of AML. It is believed that the treatment in the early stage of infection prevented further extension of the lesion. During examination of necrotic lesions occurring on the skin of patients with hematological malignancies, it is important to include mycological examination for opportunistic fungal infections, such as aspergillosis or fusariosis, which are easily overlooked by routine culture methods using conventional media with cycloheximide. This paper summarizes cases of cutaneous fusariosis in Japan.