Incomplete Urethral Duplication Associated with a Dermoid Cyst in a Dog with Urinary Obstruction.

A 20-month-old male miniature dachshund was evaluated for a 10-week history of intermittent stranguria, pollakiuria, haematuria and obstructive urolithiasis. Retrograde urethrocystography revealed a subcutaneous saccular structure in the perineal area connected to the intrapelvic urethra associated with urolithiasis. After excision of the perineal saccular structure, microscopical examination confirmed the presence of transitional epithelium lining the diverticulum, with isolated submucosal smooth muscle bundles. This structure was attached to another saccular structure lined by stratified squamous keratinizing epithelium with hair follicles, sebaceous glands and apocrine glands. An incomplete urethral duplication with dermoid cyst was diagnosed. The dog recovered uneventfully from surgery and was still urinary continent and free from clinical signs 5 months after surgery. To the authors' knowledge this is the first report of an incomplete urethral duplication with a dermoid cyst and concurrent obstructive urolithiasis in a dog.