RESUMO
Actinomycosis is a rare, indolent, and multisystemic infection caused by Actinomyces, commensal bacteria of the oral and intestinal flora. It usually occurs due to tissue disruption. It affects the abdominal region in 20% of cases, and the most common presentation is a perforated appendix. Symptoms are nonspecific, which makes differential diagnosis a challenge. We present the case of a healthy, nine-year-old boy of African ancestry with a five-month history of recurrent intermittent abdominal pain in the periumbilical and right lower quadrant areas. He recurred to the emergency department with symptoms suggestive of acute appendicitis and was submitted to an emergent laparotomy. The histologic examination revealed Actinomyces colonies compatible with the diagnosis of appendicular actinomycosis. He was treated with intravenous penicillin for a month and, subsequently, with oral amoxicillin for a year. He had complete remission of symptoms. Actinomycosis is a rare entity, particularly in children. Nevertheless, it should be considered in the differential diagnosis of an intrabdominal mass or unspecific recurrent, indolent, and abdominal pain. As symptoms are nonspecific, it can mimic other diseases. It is mostly diagnosed post-operatively, after histological examination. Early treatment is important to avoid recurrence, and, therefore, a high index of suspicion is required.