Leiomyoma of the bladder dome mimicking a urachal remnant managed with robotic partial cystectomy: a case report

Background: Bladder leiomyoma is an uncommon, benign, smooth-muscle neoplasm that can closely resemble a urachal remnant when located at the anterior bladder or dome. Imaging findings may overlap substantially with urachal remnants or other lesions and definitive diagnosis often requires surgical excision, especially in symptomatic patients or when malignancy cannot be excluded. Bladder leiomyoma arising at the bladder dome is particularly uncommon and may radiographically mimic urachal pathology, creating diagnostic uncertainty and affecting preoperative decision-making. Case Presentation: A 45-year-old woman presented with approximately six months of suprapubic discomfort and progressive stress-predominant urinary incontinence. Pelvic MRI demonstrated a 3 cm anterior/dome lesion favored to represent a urachal remnant. Cystoscopy showed an invaginating dome mass with intact mucosa, limiting the utility of transurethral biopsy. Given persistent symptoms, non-diagnostic imaging, and the inability to exclude a urachal remnant, the patient underwent robotic-assisted partial cystectomy with en bloc excision of the dome lesion and a short urachal margin. Intraoperative frozen section suggested a benign process, and final histopathology confirmed a leiomyoma. The postoperative course was uncomplicated, and the patient recovered without issues.  Conclusion: Leiomyoma of the bladder dome can clinically and radiographically resemble urachal remnants, leading to diagnostic uncertainty when mucosa is intact and imaging is equivocal. In symptomatic patients where a urachal remnant or malignancy cannot be excluded, robotic partial cystectomy provides both definitive diagnosis and symptom relief with minimal morbidity. This case underscores the importance of considering benign, smooth-muscle tumors in the differential diagnosis of anterior/dome lesions.