Severe polycystic liver disease in a cat.

Case summary: Ductal plate malformations (DPMs) are poorly documented in the veterinary literature, particularly those of the polycystic liver disease (PCLD) phenotype. A 13-year-old female spayed cat presented with progressive icterus, abdominal distension, weight loss and elevated liver enzymes. Initial empirical treatment consisting of amoxicillin/clavulanate, ursodiol and later prednisolone was attempted; however, clinical signs progressed. On abdominal ultrasound, numerous large hepatic cystic masses were noted, characterized by an anechoic center with a heterogeneous, hyperechoic wall. A post-mortem examination confirmed numerous hepatic cysts, the larger of which resulted in hemorrhage and subsequent hemoabdomen. Histologically, these cysts were determined to be of biliary origin, and a diagnosis of PCLD was assigned.

Relevance and novel information: Herein, we present a detailed report of clinical, gross and histologic findings in a cat clinically affected by PCLD. This case demonstrates that cysts present in this congenital disease can ultimately lead to hepatobiliary malfunction and clinical decline via marked expansion of cysts, compression of the liver and hemoabdomen from cyst rupture. DPMs, specifically PCLD, should be considered in cats presenting with multifocal large hepatic cysts.