Primary actinomycosis in the liver.

We present a case of a 71-year-old female with actinomycosis in the liver, which is a rare region to be primarily affected with actinomycosis. The diagnosis was done histopathologically with a partially resected liver specimen taken during surgery for choledocholithiasis. There were no clinical signs of Actinomyces infection before surgery. The hepatic lesion was a 2 cm sized nodule with histological appearances of abscess-forming suppurative inflammation with fibrosis, in which eosinophilic radiate granules with peripheral clubs were found. The Brown-Brenn stain showed Gram-positive branched filamentous bacilli, which were revealed as acid-fastness by the Ziehl-Neelsen method of Putt's modification. These findings were considered to be consistent with actinomycosis of the liver.