Abdominal mass secondary to actinomyces infection: an unusual presentation and its treatment.

Abdominal actinomycosis may appear as an abdominal mass and/or abscess. This mass can mimic a malignant tumour. The diagnosis and management of abdominal actinomycosis will be discussed through a review of the literature and a case report from our own institution. The patient was a 17-year-old boy who presented with abdominal discomfort and a palpable right lower quadrant mass defined on CT scan. He underwent en bloc resection of the mass for a presumed diagnosis of tumour of uncertain type with intestinal involvement. The diagnosis was reversed, when histology revealed filamentous organisms consistent with actinomyces. He was treated with high dose penicillin for several weeks and was discharged from the hospital taking penicillin orally. Preoperative diagnosis of abdominal actinomycosis is difficult. An accurate diagnosis is always obtained in a histological or microbiological examination, often requiring surgical resection. Recognition is important because successful treatment requires combined surgery and prolonged penicillin treatment.