Macroscopic and microscopic characterization of a uriniferous perirenal pseudocyst in a Domestic Short Hair cat

The macroscopic and microscopic features of a uriniferous perirenal pseudocyst in a castrated male 12-year-old American Domestic Short Hair cat are characterized. The development in humans and animals of a perirenal pseudocyst due to the accumulation of urine, lymph, or blood is discussed. In the presented case, microscopic evidence suggests that the pseudocyst developed following formation of a split in the kidney capsule. Emphasis is placed on the development of uriniferous pseudocysts and three proposed criteria for their development: trauma, abnormal openings that allow extravasation of urine, or urethral obstruction.