The clinicopathological features of an unusual case of a five-month-old mal
e Spanish mastiff, which was presented with clinical signs indicative of se
vere hepatic failure, are reported. Fluid replacement therapy, colloid plas
ma expanders, antibiotics and diuretic drugs were unsuccessful in improving
the animal's general condition, and euthanasia was elected by the owner. O
n necropsy, ascites and severe cirrhosis, with extensive periacinar necrosi
s, was found. Cirrhosis is a rare lesion in young dogs, The most common cau
ses are circulatory disturbances, hereditary metabolic disorders or poisoni
ng, such as aflatoxicosis and anticonvulsant therapy. The possible involvem
ent of canine adenovirus in this case is discussed.