Ultrasonographic evaluation of biliary cystadenomas in cats

The purpose of this study was to describe the ultrasonographic appearance o f biliary cystadenomas in cats and compare the findings to a similar rare f orm of liver tumor in humans. Biliary cystadenomas are uncommon, benign liv er tumors of older cats that may occur as focal or multifocal cystic lesion s within the liver. The records of 10 cats which had abdominal ultrasonogra phy and histologic diagnosis of biliary cystadenoma were reviewed. The aver age age of affected cats was 13.3 years (range 10-16 years). Eight cats wer e neutered males and two were neutered females. In three cats, the tumors w ere not seen ultrasonographically due to their small size or from being obs cured by near-field reverberation echoes. The remaining seven cats had soli tary (4 cats) or multifocal (3 cats) masses corresponding to variable ultra sonographic patterns: multilocular masses containing thin-walled cysts, hyp erechoic masses with cystic components, or masses of mixed echogenicity wit h cystic components. The masses had variable ultrasonographic patterns when multifocal disease was present. Recognizable cysts were evident somewhere within the tumors seen ultrasonographically, although sometimes the cysts a ppeared very small. The biliary cystadenomas were thought to be clinically silent. Although liver enlargement or a cranial abdominal mass was palpable in 4 cats, no consistent trend of clinical signs, CBC or serum biochemical abnormalities could be directly attributed to biliary cystadenoma. The tre atment of choice is surgical resection of the tumor, as continued growth ma y compress adjacent vital structures within the liver. The differential dia gnosis of biliary cystadenomas from other cystic liver lesions such as hepa tic cysts, hematomas, abscesses, parasitic cysts, or other liver tumors is discussed.