Dear Editor, A 65-year-old woman presented with an abdominal pain for one month. In addition, she had poor appetite and body weight loss later. She had type 2 DM with poor control and had an intrauterine device (IUD) for 20 years. Physical examination was unremarkable except lower abdominal tenderness.

Colonoscopy showed partial obstruction at sigmoid colon due to suspicious external compression. Computed tomography image of abdomen revealed inflammatory change of pelvis with multi-focal abscess around a non-radiopaque IUD (Figure 1A, arrow). Exploratory laparotomy was performed, and severe ileum adhesion around IUD in pelvis was found. Loop ileostomy was undertaken after removal of IUD. The pathologic examination of implant and peritoneal nodules revealed an organized aggregate of filamentous bacteria surrounded by suppurative inflammation and a few sulfur granules, which indicated actinomyces infection (Figure 1B). Therefore, she received amoxicillin/clavulanate for five months, and the clinical condition recovered well. Finally, she received intestinal transit reconstruction after 6 months. Actinomycosis caused by Actinomyces genus is a subacute, or chronic suppurative disease ( 1 ). Pelvic actinomycosis is usually associated with the longstanding use of IUDs ( 2 ). Because the clinical manifestation of pelvic actinomycosis is non-specific, it is hard to be differentiated actinomycosis from tuberculosis, malignancy, or other pelvic inflammatory disease. Thus, preoperative diagnosis of pelvic actinomycosis is quietly difficult to reach. However, clinician should keep alert clinical entity in the presence of pseudotumoral mesentery infiltration on CT scan, especially for women with a longstanding IUD. The outcome of pelvic actinomycosis is favorable if patient receiving the combinations of surgery and antibiotic treatment ( 2 ).