Feline digital phaeohyphomycosis due to Exophiala jeanselmei

The black nodule measuring 1 cm in diameter developed in the base of nail of an 8-year-old Japanese domestic male cat. Histological examination of the excised nodule revealed a granulomatous lesion extending from the epidermis to adjacent bone. The lesion was consisted of diffuse infiltration of macrophages with epithelioid cells and multinucleated giant cells. These macrophages contained a few to numerous yeast-like brown pigmented fungus cells with a spherical shape and dark thick wall. The PCR amplification with universal primers of the 28S ribosomal RNA gene yielded a 628-bp fragment and the direct sequence confirmed that the diagnosis of the lesion was phaeohyphomycosis caused by the pathogenic dematiaceous fungus, Exophiala jeanselmei.