Hyperlipasemia in 6 Dogs with Pancreatic or Hepatic Neoplasia: Evidence for Tumor Lipase Production

Amarked increase in serum pancreatic lipase (PL) activity with minimal concurrent increase in serum alpha-amylase activity was observed in 6 dogs with pancreatic or hepatic neoplasia. Serum PL activity ranged from 5410 U/L to 42,900 U/L, 11 to 93 times the upper reference limit for our laboratory. Neoplasms included pancreatic adenocarcinoma (n=3), endocrine carcinoma (n=2), and hepatic carcinoma of unknown origin (n=1). Tumor tissue and normal canine pancreatic tissue were stained histochemically with diastase periodic acid-Schiff to demonstrate zymogen granule content, and immunohistochemically with human monoclonal antibody for PL. Normal canine pancreatic tissue stained positive for both zymogen granule content and PL. Five of the 6 tumors stained positive for zymogen granule content, and 2 of the 6 tumors stained positive for PL. Together, the histochemical and immunohistochemical staining patterns suggested tumor PL production in 5 of the 6 dogs. Marked, unexplained hyperlipasemia may be a noninvasive indicator and biochemical marker for neoplasia of the pancreas and liver in dogs.