The first case of feline Prototheca wickerhamii infection in Japan.

A 3-year-old castrated male domestic short-haired cat was presented with nodules on the left nasal wing and the left earflap. Prototheca cells were found after excision biopsy of one of the nodules located on the left earflap. The patient cat was generally in good condition without skin problems. Prototheca wickerhamii was isolated from all 6 masses after they were surgically nucleated. The cat was recovered two months after intervention with no recurrence of skin nodules. This report deals with the first case of feline protothecosis in Japan.