A 67-year-old woman was admitted to our hospital with a productive cough, exertional dyspnea, and refractory abnormal shadowing on chest radiography that remained even after treatment for bacterial pneumonia at another hospital. Chest-computed tomography (CT) showed bilateral consolidations and widespread centrilobular micronodules. Upon further examination after hospitalization, she was diagnosed as a human T-cell lymphotropic virus type-1 (HTLV-1) carrier. We performed a bronchoscopy and detected the presence of Cryptococcus neoformans by Grocott staining of the bronchoalveolar lavage fluid. Furthermore, the cryptococcal antigen test from cerebrospinal fluid was found to be positive, and Grocott staining of lymph node obtained by percutaneous cervical lymph node biopsy detected C. neoformans. Based on these results, we made a diagnosis of disseminated cryptococcosis. We treated the condition with flucytosine and liposomal amphotericin B, following which the symptoms alleviated but radiographic images showed no improvement. The patient’s general condition gradually deteriorated, and death occurred on day 116 of hospitalization. An autopsy was conducted and its findings revealed diffuse bronchiolitis associated with C. neoformans. The findings of this study suggest that clinicians should consider cryptococcosis as a differential diagnosis in HTLV-1 carrier cases when the cause of bronchiolitis is unknown.