Spontaneous urinary bladder rupture in a dog with lymphoplasmacytic cystitis.

A 10-year-old male mixed-breed dog presented with vomiting and anuria. The dog was living indoors, and no trauma was reported by the owner. Ultrasonography and a retrograde urethrogram revealed the presence of a urinary bladder leakage. A celiotomy was performed to repair a urinary bladder tear, along with a biopsy of the urinary bladder wall. Histopathological features consisted of lymphoplasmacytic cystitis with haemorrhages and multifocal fibrotic areas within the muscular layers. Spontaneous rupture of the urinary bladder without evidence of trauma is a well-known, though rare, condition in human medicine. The chronic inflammation detected in the present case, along with fibrosis, caused the weakening of the urinary bladder wall, leading to perforation. This is the first documented veterinary case of spontaneous rupture of the urinary bladder secondary to chronic inflammation and highlights the importance of including this condition in the differential diagnosis of patients presenting with uroperitoneum without underlying trauma.