Intra-abdominal actinomycosis mimicking urachal and bladder tumor
鄭詠庭，郭博彥，周博敏
國立台灣大學附設醫院 泌尿部
國立台灣大學附設醫院 附設雲林分院 泌尿部
國立台灣大學附設醫院 附設雲林分院 病理部
Yung-Ting Cheng1,2, Po-Yen Kuo3, Po-Ming Chow1,2
1 Department of Urology, National Taiwan University Hospital
2 Department of Urology, National Taiwan University Hospital Yun-Lin Branch
3 Department of Pathology, National Taiwan University Hospital Yun-Lin Branch

Abstract
Background:
Intra-abdominal actinomycosis is a rare granulomatous inflammatory disease and mostly related to intrauterine device. Diagnosis is challenging pre-operatively because of its rarity and resemblance to malignancy.
Case Presentation
A 52 year-old woman with diabetic mellitus presented with lower abdominal pain for 3 months. Tracing back her medical history, she had intrauterine device for 20 years, which was removed 1 month before diagnosis. A large lower abdominal mass was palpable on physical examination. Computed tomography(CT) demonstrated irregular wall thickening of the bladder at superior aspect and distal ileum. Cystoscopy revealed multiple adenoid tumors over the bladder dome. The pathology of cystoscopic biopsy was cystitis cystitica. Malignancy from the bladder, urachus, or distal ileum was suspected. Trans-abdominal CT-guided biopsy yielded fibrous stroma and inflammatory cells infiltration. During laparoscopic tumor excision with distal ileum resection, fibrotic tumor mass was noted over the medial umbilical fold and adhesive to the distal ileum. The histopathology reported focal microabscess and sulfur granules. Actinomycosis was confirmed by Gomori methanamine-silver (GMS) stain. Clindamycin was administered for 2 weeks and shifted to doxycycline until 6 weeks uneventfully.
Conclusion
The majority of patients were rarely diagnosed before the operation. It is essential to differentiate the inflammatory disease from malignancy. Proper antibiotic treatment combined with surgical intervention eradicate the disease in good result.