Pulmonary Infection Caused by Mycobacterium malmoense and the Difficulties in Distinguishing It From the Pulmonary Mycobacterium tuberculosis Infection.

Mycobacterium malmoense is a rare species of non-tuberculosis mycobacteria detected in Japan that causes pulmonary infection and cervical lymphadenitis. Here, we report a case of pulmonary infection caused by M. malmoense, which was difficult to distinguish from Mycobacterium tuberculosis (Mtb) infection. A 64-year-old Japanese woman with a history of pulmonary tuberculosis had bloody phlegm, a cough, and discomfort in her chest. Chest computed tomography revealed a cavity, infiltration, and a nodule. A smear test for acid-fast bacilli was positive, a Mycobacterium avium complex transcription reverse-transcription concerted (TRC) test was negative, and an Mtb TRC test was withheld because the internal control was negative. After diluting the specimens, the internal control tested positive, and the sample tested negative. We diagnosed pulmonary M. malmoense infection based on a culture test. In conclusion, attention should be paid to the concentration of bacteria in Mtb TRC test samples, ensuring that the internal control provides expected results.

Treatment of refractory localized pulmonary nocardiosis caused by Nocardia mexicana with a combination of medication and surgery.

Pulmonary nocardiosis is a rare disease that is often difficult to cure because of its tendency to recur. Here, we report a case of refractory localized pulmonary nocardiosis caused by Nocardia mexicana. A 60-year-old Japanese woman had recurring pulmonary nocardiosis four times previously and each time she was treated with antibiotics for a sufficient duration; nevertheless, the disease continued to recur, probably because of resistance to antibiotics. As a fifth treatment, we performed middle lobe resection and pre- and post-operative antimicrobial therapy for 6 months. The combination of medication and surgery was useful for treating refractory localized pulmonary nocardiosis.

Resection of an intrapulmonary solitary fibrous tumor in the center of the middle lobe: a case report.

A 75-year-old female patient was referred to our hospital due to an abnormal shadow detected by chest X-ray. Computed tomography scans revealed a well-circumscribed nodule measuring 28 mm between B4 and B5 in the right middle lobe. Because the tumor was in the center of right middle lobe, a middle lobe resection was performed. The tumor was located within the lung and there were no obvious pleural surface changes. Postoperative histological findings showed 34-mm firm and round tumor, and well circumscribed without involving the visceral pleura. The pathologic examination revealed proliferating spindle-shaped cells with a random fascicular arrangement with continuity to the pulmonary interstitium. Not much cellular atypia was observed. Immunohistochemical staining indicated that the tumor was positive for STAT6, CD34. The final diagnosis was an intrapulmonary benign solitary fibrous tumor (SFT). Even benign intrapulmonary SFTs that have been completely resected may later become malignant and recur, and careful follow-up is necessary.