[A case of secondary pulmonary cryptococcosis complicating diabetes mellitus]

In this case, a 65-year-old man complained of fever and productive cough while being treated for diabetes mellitus at the outpatient clinic. His chest CT scan revealed multiple infiltrative lesions in both the right and left lower pulmonary lobes. He was therefore given an antibiotic on suspicion of having bacterial pneumonia, and he also received nutritional instruction in relation to diabetes mellitus, and remission resulted. However, he could not maintain sufficient glycemic control thereafter, and his pulmonary lesions persisted. Because his lesions changed into cavitied multiple nodular lesions, as seen on a chest CT scan, a transbronchial lung biopsy was performed. Histopathological examination of the biopsy specimen demonstrated Cryptococcus organisms, and the Cryptococcus antigen titer was high, which led to a diagnosis of pulmonary cryptococcosis. After oral treatment with fluconazole for 1 year and 4 months, only a small nodule in the right lower lobe and a funicular lesion in the left lower lobe remained on a chest CT scan, and the patient had neither subjective symptoms nor evidence of inflammation, although he still had a positive antigen titer for Cryptococcus. Thus, the treatment was terminated. Improvement of the clinical symptoms and of the laboratory and radiological findings demonstrated the therapeutic efficacy of this treatment.