[Study on pulmonary lesions in which nontuberculous mycobacteria were detected by percutaneous aspiration--a proposal to add "culture positivity of percutaneous aspiration material" to the bacteriological diagnostic criteria of pulmonary nontuberculous mycobacterial diseases].

OBJECTIVES: Culture positivity of percutaneous aspiration material" is not included in the current bacteriological criteria for diagnosis of pulmonary nontuberculous mycobacterial (NTM) diseases, which were published by the Infectious Diseases Society of America (IDSA)/American Thoracic Society (ATS) in 2007 or those released by the Japanese Society for Tuberculosis in 2008. However, percutaneous aspiration is a reliable technique for the detection of causative microorganisms isolated from the focus of infection. We discuss the benefits of including positive culture of percutaneous aspiration material in the bacteriological diagnostic criteria of pulmonary NTM diseases.

METHODS: We reviewed the radiological images and clinical courses of pulmonary diseases in which NTM cultures were obtained from percutaneously aspirated materials at our hospital from 1991 to 2011. Aspiration was carried out under local anesthesia, usually with fluoroscopic guidance. After percutaneous insertion of a 22-gauge needle attached to a 20-mL syringe containing about 3 mL of saline, the lesion specimen was withdrawn together with the saline. After the needle was pulled out, the aspirated material and saline were transferred to test tubes for cytological and microbiological examinations. In patients with thin-walled cavitary lesions, saline was injected into the cavity and then aspirated.

RESULTS: Percutaneous aspiration was performed in 2,742 patients and NTM disease was detected in 51 patients. Of these 51 patients, 12 had solitary nodular lesions, and in many of these patients, no NTM bacilli could be detected in the sputa or bronchial washing specimens. Mycobacterium avium was identified in 10 of the 12 cases. Four of these 10 patients were followed up after their diagnosis without any treatment: 3 showed spontaneous reduction in lesion size, while 1 patient's condition remained unchanged. Four of the remaining 6 cases were treated with anti-NTM medications, and lesion size reduced in 2 cases, while no change or deterioration was seen in the other 2. Aspiration from solitary small cavitary lesions showed a relatively high number of NTM colonies. Pneumothorax was the only complication of the aspiration procedure.

DISCUSSION: If the diagnostic criteria for pulmonary NTM diseases include positive culture in percutaneous aspiration material, the diagnosis of solitary nodular NTM lesions would become easier; at present, these lesions are often diagnosed only upon surgical resection. Further, clinical studies on the possibility of spontaneous shrinkage of the solitary lesion and the value of its medical treatment would be promoted. Aspiration can easily differentiate NTM disease from pulmonary abscess or fungal infection in patients with a solitary lesion or small cavity.