Urethral leiomyoma mimicking urethral diverticulum: a rare case report and brief literature review

Background: Urethral leiomyoma is an uncommon benign smooth-muscle tumor that typically affects women of reproductive age and presents with lower urinary tract symptoms or a periurethral mass. Preoperative misclassification as urethral diverticulum or Skene’s gland disease is frequent because clinical and imaging features overlap. Although magnetic resonance imaging (MRI) can suggest a solid periurethral mass and delineate its relation to the urethral lumen and sphincter, definitive diagnosis requires surgical excision with histopathologic confirmation. This case is noteworthy because a mid-urethral leiomyoma closely simulated a diverticulum on initial clinical assessment, and the final diagnosis hinged on targeted MRI review and en bloc vaginal excision with preservation of urethral integrity. Case Description: A 44-year-old woman presented with urethral pain and dysuria. Initial working diagnosis was urethral diverticulum. Pelvic MRI (dynamic, multiparametric) revealed a well-circumscribed 3-cm solid periurethral mass centered at the mid urethra without a demonstrable neck to the urethral lumen. The patient underwent vaginal en bloc excision via an inverted U-shaped incision under general anesthesia; the urethra was dissected free without injury. Gross specimen measured 3.8 cm × 3.0 cm. Histology showed intersecting bundles of bland spindle cells consistent with leiomyoma; immunohistochemistry (IHC) was desmin and smooth muscle actin (SMA) positive and S-100/CD34 negative, with Ki-67 ≈1%. Recovery was uneventful with acetaminophen-only analgesia; Foley catheter was removed after 1 day, and she was discharged on postoperative day 1. At 3 months, there were no complications and dysuria had resolved. Conclusions: Mid-urethral leiomyoma can mimic urethral diverticulum. Careful MRI review for a solid lesion without luminal communication, followed by complete local excision that preserves urethral integrity, leads to accurate diagnosis and excellent short-term outcomes. This report provides practical imaging and operative cues for periurethral smooth-muscle tumors.