[A case of ileocecal actinomycosis treated by preoperative antibiotic treatment to reduce mass size followed by surgical resection]

Abstract

A 65-year-old woman presented to a nearby clinic with a painful mass in the right lower abdominal region. She was suspected of having an appendiceal tumor on abdominal computed tomography (CT) and was referred to our hospital for surgery. Blood testing revealed increased inflammatory markers. Contrast-enhanced abdominal CT revealed a mass with poorly defined margins in the ileocecal region, which was adjacent to the external iliac vessels. A barium enema revealed unilateral wall deformities in the cecum through to the terminal ileum, whereas lower gastrointestinal endoscopy showed no clear epithelial tumor component. The patient was clinically diagnosed with ileocecal actinomycosis and treated with high-dose penicillin G. On day 15 of treatment, contrast-enhanced abdominal CT showed a reduction in mass size. On day 26, right hemicolectomy (D3) with combined resection of the external iliac vein (which could not be separated from the mass) was performed. Pathological examination revealed granulation tissue with granules of actinomyces, with filamentous bacteria detected by Grocott staining. With no evidence of malignancy, the final diagnosis of ileocecal actinomycosis was made. This report presents a case of clinically suspected ileocecal actinomycosis treated by preoperative antibiotic treatment to reduce mass size, followed by surgical resection.