Rare Abdominopelvic Actinomycosis Causing an Intestinal Band Obstruction and Mimicking an Ovarian Malignancy

Actinomyces israelii, a commensal of the bronchial and gastrointestinal tracts, is responsible for the majority of actinomycostic infections in humans. Actinomycosis has widely varying clinical presentations ranging from asymptomatic states to infiltrative mass lesions that mimic malignant abdominopelvic disease. Described as one of the most misdiagnosed diseases, actinomycosis poses challenges to accurate preoperative diagnosis. A 67-year-old woman with no significant medical history presented with features of acute intestinal obstruction. Computed tomography revealed a terminal ileal stricture causing intestinal obstruction and a right ovarian mass lesion. On laparotomy, a granular mass (2×2 cm) at the base of the mesentery and a right ovarian hard nodular growth (3×3 cm) were found that were connected by a dense fibrotic band, causing ileal obstruction with a transitional zone that was 10 cm proximal to the ileocecal junction. The mesenteric granular mass was excised together with the dense fibrotic band, and a right salpingo-oophorectomy was also undertaken. On postoperative histopathological examination, band formations by dense inflammatory tissue with neutrophilic infiltration were observed; moreover, there were sulfur granules that showed a positive reaction on Periodic Acid Schiff staining. The resected ovarian parenchyma showed infiltration by bacterial colonies with Splendore-Hoeppli phenomenon and evoked dense neutrophilic infiltration. The postoperative period was uneventful, and the patient was placed on penicillin therapy for a year. Abdominopelvic actinomycosis should constitute part of the differential diagnosis when evaluating mass lesions, especially in elderly women with a history of intrauterine device (IUD) use.