A 70-year-old woman was admitted to our hospital on suspicion of liver tumor on regular abdominal ultrasonography. The abdominal ultrasonography identified a solitary, low-echoic lesion measuring 17mm in diameter in S7. This lesion was not enhanced in any phase of contrast-enhanced computed tomography (CT), and thus we performed a liver biopsy. Histopathological examination revealed a caseating granuloma. The chest CT showed pulmonary nodules, and Mycobacterium intracellulare was cultured from the bronchoalveolar lavage fluid. We diagnosed the individual with a Mycobacterium avium complex infection, and suspected that this was the cause of the solitary liver lesion.