Pulmonary Mycobacterium shigaense Infection with Hemoptysis: Two Surgically Resected Case Reports

Mycobacterium shigaense (M. shigaense) is a rare nontuberculous mycobacterium (NTM) first reported in Japan in 2012. Only a few cases of pulmonary infection have been described, all treated medically. No surgically resected cases or cases presenting with hemoptysis have been reported to date.

We report 2 immunocompetent patients with pulmonary M. shigaense infection presenting with persistent hemoptysis who were successfully treated surgically. Case 1 was a 67-year-old woman with daily hemoptysis caused by a nodular lesion in the right middle lobe. Despite long-term antimicrobial therapy, hemoptysis worsened, and a robot-assisted right middle lobectomy was performed. Hemoptysis resolved immediately after surgery, and no recurrence was observed during 1 year of follow-up. Case 2 was a 68-year-old man with repeated moderate hemoptysis caused by a cavitary lesion in the left upper lobe. Robot-assisted surgery was attempted but converted to thoracotomy due to severe adhesions, and left upper division segmentectomy was performed. Hemoptysis was resolved completely after surgery. In both cases, M. shigaense was identified by culture and genomic analysis, and histopathology showed epithelioid granulomas with caseous necrosis.

Pulmonary M. shigaense infection can cause clinically significant hemoptysis. Surgical resection combined with antimicrobial therapy was effective for symptom control in both cases. Surgery should be considered for localized disease refractory to medical treatment.