An 82-year-old Japanese man who previously had descending colon cancer and underwent partial resection showed a growing solitary pulmonary nodule, suspected as lung cancer, on follow-up computed tomography. Thoracoscopic partial lobectomy was therefore performed. The surgical specimen showed granulomatous lesions with necrosis. Mass spectrometry was performed on the sputum specimen collected after surgery, which identified Mycobacterium lentiflavum infection. Antibiotics were not prescribed following surgery, and the patient has not experienced recurrence 2 years since the surgery. To our knowledge, this is the second case of solitary pulmonary nodule and the first case of M. lentiflavum infection treated via surgical resection.