The case was a 58 year-old female. During hospitalization for the treatment of pulmonary tuberculosis, she complained of pain in the left hypochondriac region. Abdominal CT revealed a mass between the abdominal wall and left lobe of the liver. Metastatic liver carcinoma was suspected by aspiration cytology, but no primary tumor could be identified. Therefore, an exploratory laparotomy was done, and the mass proved to be a subperitoneal tuberculoma. Tuberculous lymphadenitis was also found in lymph nodes of the upper abdominal cavity. Tuberculosis in the abdominal cavity has been rare in recent times in Japan. Therefore, this case provides valuable experience in the differential diagnosis of an abdominal mass.