Polypoid Cystitis: A Retrospective Case-Series of 112 Dogs

Polypoid cystitis (PoC) in dogs is associated with chronic inflammatory bladder conditions and is discovered during evaluation for signs of lower urinary tract disease, or incidentally.

To describe PoC in dogs evaluated in an academic practice.

Dogs with confirmed (n = 59) or presumptive (n = 53) PoC were evaluated between January 2004 and October 2020.

For this retrospective study, medical records were searched for PoC.

The most common presenting signs of 112 dogs with PoC were hematuria (n = 42; 38%), stranguria (n = 28; 25%), and pollakiuria (n = 25; 22%). Polyps were found incidentally (n = 13; 12%). Urinary tract infection (UTI; n = 61; 54%) or urolithiasis (n = 38; 34%) was a common presumptive cause. Escherichia coli (n = 39; 53%), Enterococcus faecalis (n = 14; 19%) and Staphylococcus pseudintermedius (n = 5; 7%) were isolated from dogs with UTI. Ultrasonographic findings (n = 101) included polypoid structures (n = 44; 44%), broad-based masses (n = 16; 26%), and bladder wall thickening (n = 25; 25%); mostly in the cranioventral bladder apex (n = 56; 80%). Of 41 specimens tested, none had evidence of the BRAF V595E mutation. Urinary tract neoplasia was not reported in any dog during follow-up (range 1 month-8.4 years; median 8 months). Interventions included antibiotic or anti-inflammatory administration, and surgical or cystoscopic ablation. During follow-up, recurrent signs of lower urinary tract disease were reported in 23 (20%) dogs.

History of either UTI or urolithiasis, compatible imaging findings, and absence of detectable BRAF V595E mutation support the presumptive diagnosis of PoC in dogs. Affected dogs have a good prognosis, warranting differentiation from other urinary tract diseases.