First Japanese Case of Chromoblastomycosis Caused by Phialophora europaea

We report the case of chromoblastomycosis caused by Phialophora europaea in Japan. A woman in her 60s presented with an erythematous plaque with pustules on her right buttock. Skin biopsy was performed, and the specimen showed hyperkeratosis, acanthosis with parakeratosis, and dermal granulomatous infiltrate with multinucleated histiocytic giant cells. Muriform cells were found in the inflammatory tissue. The patient was diagnosed as having chromoblastomycosis and was referred to our department. A direct examination of the crust using potassium hydroxide solution revealed the presence of fungal elements as muriform cells. The culture of the crust revealed felty, grayish-to-black colonies. The isolate was identified as P. europaea by molecular identification of the internal transcribed spacer sequences on the rRNA gene. The patient's condition improved after surgical excision, and oral itraconazole was administered postoperatively. To our knowledge, this is the first reported case of a skin infection caused by P. europaea outside of Europe.