Hyperalbuminemia associated with hepatocellular carcinoma in a dog

A 12-year-old, neutered male, mixed-breed dog was presented to The Ohio State University Veterinary Teaching Hospital with a history of weight loss and weakness. Laboratory abnormalities reported by the referring veterinarian during the past year included increased alkaline phosphatase (ALP) activity, hyperalbuminemia, and nonregenerative anemia. On referral, the dog appeared hydrated and had moderate muscle wasting and hepatomegaly. A large lobular hepatic mass was observed ultrasonographically. Laboratory results included mild to moderate nonregenerative anemia, urine-specific gravity of 1.035, 3+ proteinuria, increased serum activities of alanine aminotransferase (229 U/L, reference interval 10-55 U/L), ALP (813 U/L, reference interval 15-120 U/L), and the steroid-induced isoform of ALP (676 U/L, reference interval 0-6 U/L), marked hyperalbuminemia (5.3 g/dL, reference interval 2.9-4.2 g/dL), and an increased A/G ratio (1.7). Hyperalbuminemia was confirmed by reanalysis on 2 different analyzers and by agarose gel electrophoresis, and colloid osmotic pressure (COP) was markedly increased (42.5 mmHg, reference interval 20-25 mmHg). Cytologic examination of a fine-needle aspirate of the hepatic mass indicated hepatocellular proliferation; histologic examination of an excisional biopsy confirmed hepatocellular carcinoma. Three weeks after surgery, the albumin concentration, A/G ratio, COP, and ALT activity had normalized, but ALP activities remained high. We hypothesized that hyperalbuminemia developed secondary to hepatocellular carcinoma due to increased synthesis of albumin by malignant hepatocytes or due to decreased negative feedback from impaired hepatocellular osmoreceptivity. Hepatocellular carcinoma has been associated with paraneoplastic secretion of other proteins, but hyperalbuminemia has been reported only once in a human patient and has not previously in dogs.