Lower obstructive uropathy associated with pelvic lipoma in a cat.

This report describes a case of lower urinary tract obstruction caused by pelvic lipoma in a two-year-old male domestic shorthair cat that was admitted to the emergency room with failure to urinate during the past 2 days. Clinical examinations revealed hypothermia, pale mucous membranes, tachypnea, bradycardia, and severely enlarged bladder. Diagnostic imaging showed distention of the bladder, compression of the bladder neck, and increased thickness of the bladder wall. After the cat died, multiple lobulated fat-like masses were observed in the pelvic cavity, which caused bladder neck obstruction. By histopathological examination, the masses were diagnosed as lipoma; also proliferative cystitis, hydropic degeneration of proximal tubular epithelial cells, and interstitial pneumonia were observed in the bladder, kidney, and lung samples, respectively. Given the frequency of cats with urinary obstruction, pelvic lipoma should be considered as a differential diagnosis in future cases with similar history and findings.