[Acute retrocecal appendicitis caused by an Actinomyces israelii mixed infection].

We report the rare case of a retrocecal appendicitis in an adult caused by an Actinomyces israelii mixed infection. Suspecting an acute appendicitis the explorative laparotomy was performed. Appendectomy with extensive drainage of the abscess and subsequent high-dose penicillin therapy over several months were the definitive treatment, resulting in complete healing. Special features of clinical symptomatology and problems concerning diagnosis and differential diagnosis are discussed.