Long-term outcome after resection and reconstruction using vaginourethroplasty for distal urethral leiomyosarcoma in a female dog.

Abstract

Objective: To describe vaginourethroplasty-based resection and reconstruction of distal urethral leiomyosarcoma in a female dog and report long-term outcomes.

Study design: Case report.

Animals: One 10-year-old spayed female mixed-breed dog.

Methods: Retrograde urethrovaginography identified a distal urethral filling defect. Two days later, contrast-enhanced computed tomography under general anesthesia demonstrated a 17 × 17 × 24 mm distal urethral mass without distant metastasis; blind biopsy performed immediately afterward was nondiagnostic. Because stranguria progressed, surgery was performed 20 days after presentation in two sequential phases during a single general anesthetic. The proximal urethra was anastomosed end-to-end to the vaginal stump through a ventral approach. Bladder neck cystopexy was added, and the distal urethra, mass, and adjacent vaginal mucosa were removed en bloc through a perineal approach, followed by vaginal reconstruction and vulvoplasty.

Results: The mass was initially diagnosed as undifferentiated sarcoma and later classified as leiomyosarcoma after immunohistochemical reevaluation. The mitotic count was 12 per 10 high-power fields, and the distal margin was minimal. Voluntary urine storage and voiding were maintained; mild urinary incontinence was managed medically. Approximately 13 months after surgery, a right inguinal lymph node lesion morphologically compatible with metastasis from the prior urethral mesenchymal malignancy was excised. At 49 months after presentation, no local recurrence or new distant metastasis attributable to the urethral lesion had been detected.

Conclusion: In this dog with distal urethral leiomyosarcoma, the combined ventral and perineal approach was associated with preserved urinary function; no local recurrence was detected through 49 months after presentation.