Case presentation
A 77-year-old man with a history of rheumatoid arthritis (RA) for 15 years was admitted to our department due to organizing pneumonia secondary to RA. His symptoms and radiological findings improved after initiating corticosteroid therapy (500 mg/day methylprednisolone for three consecutive days, followed by 1 mg/kg/day prednisolone), which was gradually tapered in the outpatient department. He had a medical history of diabetes mellitus. He had smoked 20 cigarettes a day for approximately 40 years. He had been treated with iguratimod (25 mg/day) and prednisolone (3 mg/day) for RA. Approximately 1 year after discharge, he complained of cough and sputum production. A physical examination revealed no acute distress, with a blood pressure of 135/67 mmHg, heart rate of 87 bpm, body temperature of 37.1°C, and respiratory rate of 20/min. A neurological examination showed no abnormalities. Laboratory tests showed elevated C-reactive protein level and renal dysfunction. The levels of serum β-D glucan, MPO-ANCA, and PR3-ANCA were normal. Tests for Aspergillus antigens, interferon-gamma release assays for Mycobacterium tuberculosis, and tests for anti-Mycobacteria antibody were negative (Table 1). CT showed multiple cavities in the right lung (Figure 1A). Sputum culture resulted in the isolation of C. neoformans , and tests for serumCryptococcus antigens were positive (antigen titer: 1:64). Bronchoscopy was performed, and culture of the bronchial lavage fluid was found to be positive for C. neoformans. Therefore, the patient was diagnosed with pulmonary cryptococcosis. Lumbar puncture was performed, which revealed clear cerebrospinal fluid with a normal cell count and normal protein and glucose levels. Tests for the cryptococcal antigen in the cerebrospinal fluid were negative. The patient received fluconazole orally (400 mg/day), but the treatment was interrupted due to drug eruption 1 month later. Subsequently, he was treated with oral administration of itraconazole (200 mg/day). After the initiation of this treatment, his symptoms and inflammatory responses in laboratory tests improved. CT showed that the walls of the lesions became thin and they coalesced with each other (Figure 1B). Six months after the initiation of treatment, he complained of exertional dyspnea. CT revealed enlarged multiple cysts, which may have caused his symptoms (Figure 1C). The cryptococcal antigen titer was 1:4, and no increase in the antigen titer was observed thereafter; the treatment was completed in 9 months.
Although no significant increase in the size of cystic lesions was observed after the end of treatment, exertional dyspnea of the patient persisted and the risk of pneumothorax was high; therefore, the patient is being followed up carefully.