• Insulinoma - tumor that produces insulin

Lucy, a 6y female Border Collie, presented to us at West Midlands Referrals with worryingly low glucose levels caused by an insulinoma, a pancreas tumour. The pancreas has two main jobs – it produces enzymes to be delivered to the gastrointestinal tract to digest food, and it produces the hormones insulin, which controls blood sugar. Insulin moves glucose from the 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 a recent history of weakness, low blood sugar and 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. 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 before surgery to remove the “limb” of the pancreas containing insulinoma. The mass was approximately 1.5cm in 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 the risk of leaving an area of the pancreas still producing enzymes but with no adequate duct drainage into the intestines.

Histology was reported as Insulinoma, a carcinoma arising from the Beta cells in the pancreatic islets. This potentially malignant tumour 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 well post-op but developed diabetes about five 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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