[Autopsy case of pulmonary zygomycosis and pneumocystis pneumonia in a patient with interstitial pneumonia treated by corticosteroid therapy].

We report a 75-year-old man with pneumoconiosis, interstitial pneumonia and diabetes mellitus, who had carcinoma of the buccal mucosa. After resection of the carcinoma, he was given corticosteroids for the deterioration of interstitial pneumonia, but 38 days after initiating steroid therapy, he was admitted to our hospital with severe hypoxemia and multiple cavitary lesions superimposed on ground-glass attenuation in both lung fields. The Aspergillus antigen was positive in his serum and examination of his bronchoalveolar lavage (BAL) fluid revealed mixed infections with filamentous fungus and Pneumocystis jirovecii. Pulmonary aspergillosis and pneumocystis pneumonia with an immunocompromised state was diagnosed, and voriconazole, sulfamethoxazole-trimethoprim and high-dose corticosteroids were given. At 20 days after these treatments he developed bloody sputum, and Cunninghamella bertholletiae was isolated from the BAL fluid obtained at admission. A diagnosis of pulmonary zygomycosis was finally established. Amphotericin B therapy was started, and the dose was increased thereafter. Despite intensive treatment he died 18 days later. Histological examination of lung tissue obtained at autopsy showed invasive growth of zygomycetes in the necrotic tissue and the cavity wall. To the best of our knowledge, this is the first report of concurrent Cunninghamella bertholletiae and Pneumocystis jirovecii infection during steroid therapy for interstitial pneumonia.