Prolonged Survival in an Aged Labrador Retriever with a Metastatic Insulinoma

Abstract

This case report highlights an unusually prolonged, asymptomatic, disease-free interval in an aged male Labrador retriever that underwent partial pancreatectomy for a functionally active pancreatic insulinoma with histologically confirmed hepatic metastasis. The patient developed pancreatitis and nonseptic suppurative peritonitis 24 hr after surgical resection of the insulinoma and was managed medically until discharge. Three mo after surgery, the dog was diagnosed with exocrine pancreatic insufficiency (EPI) that was effectively managed with parenteral pancreatic enzymes. Due to normal glucose levels 3 mo postsurgically, liver samples from the initial surgery were resubmitted for immunohistochemistry. Results confirmed insulinoma metastasis with insulin expression. Ten mo postsurgically, the blood glucose was normal and serum insulin levels were slightly above the upper reference limit. The first hypoglycemic episode was documented 23 mo postoperatively, which was effectively managed with prednisone. The cause for the prolonged disease remission and survival was unknown, but was possibly a result of pancreatitis and peritonitis, partial spontaneous regression of metastatic lesions, or idiopathic. Despite life-threatening postoperative complications, this patient enjoyed a profoundly longer than expected survival. This case highlights the importance of removing the primary tumor (insulinoma) despite the presence of metastatic disease.

Insulin therapy in a dog diagnosed with a metastatic insulin‐secreting neuroendocrine tumour

“…6 Additional reported post-operative complications include pancreatitis, peritonitis and exocrine pancreatic insufficiency. 5,7 In contrast, medical management involves a multimodal approach to induce insulin resistance, tumour lysis and decreased insulin production. 3 This is achieved via the initiation of multiple pharmaceuticals and dietary modifications.…”

“…Transient diabetes mellitus (DM) is a recognised post‐operative complication of surgically managed canine insulinomas, with prevalence data ranging between 10% and 12% 6 . Additional reported post‐operative complications include pancreatitis, peritonitis and exocrine pancreatic insufficiency 5,7 . In contrast, medical management involves a multimodal approach to induce insulin resistance, tumour lysis and decreased insulin production 3 .…”