Hepatic actinomycosis after total pancreatectomy: A case report

Introduction and importance: Hepatic actinomycosis (HA) is a rare infection mimicking a malignancy. HA after total pancreatectomy for a pancreatic tumor has not been reported. Case presentation: A 70-year-old woman with a history of gastrectomy and sigmoidectomy for benign lesions, underwent a total pancreatectomy for a non-invasive, intraductal papillary mucinous carcinoma (IPMC). She required partial resection of the transverse colon due to insufficient blood flow and had an anastomotic failure. Four months later, she developed a fever and effusion from the upper abdominal midline incision. No bacteria were cultured from the effusion. Contrast-enhanced computed tomography demonstrated an 80-mm iso-vascular liver mass. A slightly high-signal intensity on T2-weighted magnetic resonance imaging was demonstrated. Positron emission tomography (PET) showed a standardized uptake value of 11.9 at the liver mass. The percutaneous liver biopsy did not establish a diagnosis. Because a malignancy could not be ruled out, an exploratory laparotomy was performed. A tissue sample revealed aggregates of branched filamentous microorganisms; actinomycosis was diagnosed. Oral amoxicillin for 4 months resolved the mass. Clinical discussion: This patient had several causative factors for HA, including multiple surgical procedures involving the gastrointestinal tract, reconstruction of the biliary tract, anastomotic failure of the transverse colon, and diabetes mellitus following total pancreatectomy. Based on the past treatment history for IPMC and PET findings mimicking a malignancy, a laparotomy was performed to biopsy the lesion. Typically, penicillin is recommended for >6 months. Conclusion: A rare case of HA mimicking a malignancy after a total pancreatectomy for IPMC is presented.