Combination therapy for an elderly patient with chromoblastomycosis caused by Fonsecaea monophora: a case report

We report the first case of combined treatment using oral drugs, thermotherapy, and carbon dioxide fractional laser for an elderly patient with skin chromoblastomycosis caused by Fonsecaea monophora. Chromoblastomycosis is a chronic and refractory granulomatous disease of the skin and subcutaneous tissues caused by a group of dematiaceous fungi, which can cause teratogenesis, disability, and even cancer. One of the subtypes, F. monophora, is not only limited to the skin and subcutaneous tissues but also affects the central nervous system. Therefore, a timely and clear diagnosis, as well as active and effective treatment, are particularly important. This case report presents a 75-year-old male patient whose left forearm had a plaque with mild pruritus for more than three years. The patient's skin lesions were histopathologically examined, and the fungus on the surface of the scabbed skin was examined by fluorescence microscopy and cultured. The strains obtained by the culture were identified by morphological and molecular biology, and a drug susceptibility test was conducted in vitro. Histopathology revealed hyperkeratosis of the epidermis with pseudoepitheliomatous hyperplasia, chronic granulomatous changes in the dermis, and brown thick-walled sclerotic corpuscles both inside and outside giant cells. Septate hyphae and sclerotic corpuscles could be observed in the fungus on the surface of the scabbed skin by fluorescence staining, and black villous colonies could be observed in vitro. Under the scanning electron microscope, rhinocladiella was the primary sporulation type, and the conidia were oval. Molecular identification results showed that the similarity between its internal transcribed spacer (ITS) sequence and that of F. monophora, a Chinese strain (IFM41705), was the highest, reaching 100%. The results of the drug susceptibility test showed that the minimum inhibitory concentrations of itraconazole and voriconazole were 0.125 mg/L and 0.06 mg/L, respectively. The patient was given oral itraconazole 0.2 qd, combined with local thermotherapy and carbon dioxide fractional laser treatment. After 16 weeks, the microscopic examination of the fungus was negative, showing good efficacy.