Hepatic actinomycosis infiltrating the diaphragm and right lung

Hepatic actinomycosis is a rare infectious disease caused by an anaerobic gram-positive bacterium of the genus Actinomyces. Herein, we describe an unusual case of hepatic actinomycosis involving the diaphragm and right lung. A 41-yr-old man was admitted to Wakayama Medical School Hospital presenting with right back pain and cough. Computed tomography and magnetic resonance image revealed a 5 x 10 cm tumor in the anterior superior segment of the liver, which extended to the diaphragm and right lung. Angiography demonstrated a hypervascular tumor and the enlarged right inferior phrenic artery feeding around the tumor. The patient underwent a hepatectomy with partial resections of the diaphragm and the right middle pulmonary lobe. Microscopically, the specimen showed sulfur granules and was positive for Gram stain and Grocott stain and negative for Ziehl-Neelsen stain. These findings were consistent with actinomycosis of the liver. His postoperative course was uneventful and no recurrence was observed 1 yr postoperatively. Although there are at least 36 well-documented cases until 1993, no other report has been found infiltrating the diaphragm and lung.