A case of pulmonary granuloma associated with mycobacterium avium complex infection arising from the surgical margin after segmentectomy

The patient was a 50-year-old man with a history of right S9 + 10 segmentectomy for lung carcinoid at another hospital 4 years and 9 months ago. Two years and nine months after the surgery, a nodule was noted at the surgical margin. Furthermore, 9 months later, the nodule was enlarged and detected a strong accumulation on positron emission tomography–computed tomography. Therefore, the recurrence could not be denied and surgery was performed. The intraoperative pathological diagnosis was inflammatory granuloma, which was then removed by wedge resection. A culture of the tumor content showed mycobacterium avium complex (MAC). The final pathological diagnosis was a pulmonary inflammatory granuloma associated with MAC infection. Although a number of studies showed the risk of foreign body granuloma or an inflammatory pseudotumor after pulmonary resection with surgical staples, in this case the prior segmentectomy was carried out with electrical cautery alone. A nodule detected at the surgical margin after segmentectomy should be suspected to be an inflammatory change, in particular granuloma formation, as well as tumor recurrence and second primary lung cancer, even if the segmentectomy was done without staplers.