Hepatic actinomycosis: an overview of salient features and outcome of therapy

A 34-y-old African-American male developed Actinomyces liver abscess 8 months after appendectomy. Review of the English language literature revealed 56 additional cases of hepatic actinomycosis. Affected patients were typically immunocompetent, had a wide age range (4-86 y) and were predominantly male (70.2%). Infection was frequently (80.7%) cryptogenic, presenting with fever (83.3%), abdominal pain (74.5%) and weight loss (50.9%) over a 3.7 +/- 5.1 month period. The most common radiographic finding was a single hypodense mass/abscess (68.4%). Extension to surrounding tissues was evident in 19 cases (33.3%). Diagnosis was usually accomplished microscopically and culture was often (33.3%) negative. Infection was often (35.2%) mixed, usually with anaerobic bacteria. A surgical or percutaneous approach was diagnostic in 29/35 (82.9%) and 24/33 (72.7%) cases, respectively. The overall mortality rate was 8.8%; it was 10.7% with medical therapy alone and 4.0% using a combined medical/intervention approach (p = 0.6). In conclusion, hepatic actinomycosis is a rare subacute infection that may mimic neoplasm. It is usually cryptogenic, is more common among immunocompetent individuals and male subjects and is highly responsive to medical therapy.