A rare case of primary urachal actinomycosis mimicking malignancy.

Primary actinomycosis occurring in urachal remnants is rarely documented in literature and may mislead the clinicians to diagnose urachal carcinoma. A 50-year-old man came with complaints of lower abdominal pain, dysuria, and dribbling of urine for 2 months. A vague mass of 7 cm was palpable in the suprapubic region. Imaging of the abdomen revealed an irregular mass seen superior to fundus of the urinary bladder appearing adherent to mesentery and bowel loops, suggesting an urachal remnant associated lesion with infiltration. Provisional diagnosis of urachal carcinoma was considered. Excision of the mass with partial cystectomy and resection of involved ileal segments were done. Microscopic examination revealed actinomycotic colonies surrounded by microabscesses and dense inflammatory fibrotic lesion. Small intestinal segments showed a similar lesion in the serosa.