Granuloma associated with Trichosporon asahii infection in the lung: Unusual pathological findings and PCR detection of Trichosporon DNA.

We describe the first case of a Trichosporon asahii infection of the lung characterized by an epithelioid granuloma with multinucleated giant cells. The patient died of respiratory failure due to lung fibrosis and lung cancer. Autopsy showed primary lung cancer with metastasis, lung fibrosis, and a focal infectious lesion containing the filamentous and yeast forms of a fungus. From its shape the fungus was judged to be Trichosporon, but unusual pathological findings revealed an epithelioid granuloma with multinucleated giant cells surrounding the hyphae and yeast cells. Immunohistochemical staining was performed using the specific Trichosporon spp. monoclonal antibodies and DNA identificationn was done by the PCR. The results showed this case to be a localized Trichosporon asahii infection. Hypersensitivity pneumonitis (HP) due to Trichosporon spp. with its pathological finding of inflammation with granuloma is common, but infections with granulomatous inflammation are extremely rare. This case suggests that Trichosporon infection may develop into granuloma with multinucleated giant cells.