[Abdominal actinomycosis: a rare differential diagnosis to colon carcinoma and Morbus Crohn].

Abdominal actinomycosis is a rare, chronic and slowly progressive granulomatous disease. The clinical presentation of abdominal actinomycosis shows a great variability and it often mimics other intraabdominal pathologies like chronic inflammatory bowel diseases or malignancies. A correct diagnosis can rarely be established before radical surgery especially in patients with advanced tumors and an acute clinical presentation. Actinomyces are considered to be residential saprophytes in the gastroinstetinal tract and require a mucosal lesion to cause an opportunistic infection. Microbiological culture is the gold standard for diagnosis, despite high false-negative rates in daily routine testing. Therefore, actinomycosis is diagnosed more often histopathologically by detection of sulfur granules in the surgical specimen. The postoperative treatment of choice is intravenous followed by oral penicillin over a few weeks due to good response and low resistance rates. There are no evidence based recommendations concerning the duration of antibiotic treatment, but a treatment of at least 4 weeks depending on the clinical course is advisable to achieve permanent recovery. The following case report deals with a severe clinical course of an abdominal actinomycosis. The 49-year-old female patient had to be operated as an emergency under suspicion of an advanced colonic carcinoma with bowel obstruction. She needed an elaborate operative and postoperative therapy.