UNILATERAL PERINEPHRIC PSEUDOCYST OF UNDETERMINED ORIGIN IN A DOG

Unilateral perinephric pseudocyst of undetermined origin was diagnosed in a 13^1/2 year old dog with a history of recurrent urinary tract infections. A presumptive diagnosis of pseudocyst was based on radiographic and sonographic findings. In survey radiographs, asymmetrical unilateral renomegaly was seen. The mass was anechoic. There was absence of opacification of the mass during excretory urography. A celiotomy was performed for removal of the perinephric mass, and histologic review of this structure confirmed it to be a pseudocyst. Perinephric accumulation of fluid is a rare condition in domestic animals. Seven examples of perinephric pseudocysts have been previously reported in the cat. Predominant clinical findings include progressive abdominal distension and nonspecific signs of renal disease. The presence of unilateral or bilateral renomegaly is a characteristic radiographic feature. This clinical report describes the first case of perinephric pseudocyst diagnosed in the dog.