• Insulinoma - tumor that produces insulin

Lucy, a 6y female Border Collie presented with worryingly low glucose levels, caused by an insulinoma, a tumour of the pancreas. The pancreas has two main jobs – it produces enzymes to be delivered to the gastro-intestinal tract to digest food, and it produces hormones insulin which controls blood sugar. Insulin moves glucose from blood into body cells.

insulinoma1Insulinomas are tumours that produce insulin. Too much insulin leads to low glucose levels and there’s not enough left for organs like the brain that depend on it. The consequence is weakness, collapse, coma and even death. Lucy had had a recent history of weakness, low blood sugar and has had seizures every 2-3 weeks or so for a couple of months. The owner was very well informed and capable and had been controlling signs as far as possible with diet to that point. But as the tumour got bigger and made more and more insulin, the problem progressed.

Our colleague Mayra did an ultrasound scan and characterised the mass prior to surgery for removal of the “limb” of the pancreas containing the insulinoma. The mass was approximately 1.5cm diameter and in the right limb of the pancreas.

The mass was identified and carefully dissected with apparent gross margins. The associated part of the pancreas was removed to avoid risk of leaving an area of pancreas still producing enzymes but with no effective duct drainage into the intestines.

Histology was reported as Insulinoma, a carcinoma arising from the Beta cells in the pancreatic islets. This is a potentially malignant tumour which may spread to the lymph nodes, liver, mesentery and omentum. It was not confirmed that we had been able to achieve surgical margins around the mass and so regrowth was a possibility.

She did really well post op, but developed diabetes about 5 months post-op. The owner controls this with insulin injections.

About a year on she’s still doing well, and we plan to re-scan her before too long.

Warning: the images further down are not for the squeamish!

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