Abdominal wall actinomycosis simulating a neoplasm

Abstract

Actinomycosis is a rare, chronic granulomatous infection mainly caused by Actinomyces israelii. It can affect the cervicofacial, thoracic, and abdominopelvic regions. Pseudotumoral forms are uncommon and must be distinguished from tumors. We report the case of a 32-year-old female patient with a progressively enlarging abdominal mass with signs of inflammation. The computed tomography scan revealed an abdominal wall mass probably adhered to the colon. During surgical exploration, dense adhesions were identified between the abdominal wall and the transverse colon without involvement of the intestinal lumen. The patient underwent right colon resection with en bloc resection of the abdominal wall. Pathological examination identified PAS-positive filamentous structures suggestive of actinomycosis and antibiotic therapy was initiated, with a favorable outcome. This case highlights the need to consider actinomycosis during the differential diagnosis of abdominal wall tumors.