Glucagonoma

Question 1

Glucagonoma

Answer 1

Glucagonoma

Glucagonomas are small tumours, almost always found in the pancreas, and frequently malignant. They present with diabetes mellitus, venous thrombo-embolism and the classical rash of necrolytic migratory erythema - a red, blistering rash.

Question 2

Glucagonoma - Example Question

Answer 2

A 75-year-old man presents to referred to the diabetic clinic by his general practitioner with newly identified hyperglycaemia. He had presented with a two month history of polyuria, polydipsia and diarrhoea and was found to have a blood sugar of 18.4 mmol/L. Over this time period he had lost 6kg and now weighed 61kg. His past medical history includes hypertension and a deep vein thrombosis which was diagnosed three months ago. He takes amlodipine 10mg and warfarin.

What is the diagnosis?

	> Glucagonoma
	Type one diabetes mellitus
	Cushing's syndrome
	Drug induced diabetes
	Type two diabetes mellitus

Glucagonoma is an uncommon tumour of the pancreatic alpha cells. It can present with new or worsening diabetes mellitus, venous thromboembolism, the classic rash of necrolytic migratory erythema (a painful, pruritic maculopapular rash occuring typically at sites of friction with clothing…) and other symptoms of hyperglucagonaemia (diarrhoea, weight loss, anaemia). Type one diabetes mellitus can of course present with the osmotic symptoms of hyperglycaemia and weight loss but would be unlikely in a patient of this age with no history of auto-immune disease. Type two diabetes mellitus would be uncommon in a non-obese older patient and is less likely to present with osmotic symptoms.

Question 3

Glucagonoma - Example Question

Answer 3

A 49-year-old man presents with feeling under the weather. On further questioning he reports that he has been feeling tired and weak for the past few weeks and his wife has noticed that he as lost some weight, although he states that his appetite has not decreased and if anything he is feeling more thirsty and going to the toilet several times a night. Over the last couple of days he has noticed a rash develop around his groin, which is now present on his buttocks. On examination, there are patches of red with irregular borders and crusting.

A fasting blood test is arranged and reveals a blood glucose of 9.2 mm/l.

What is the next most appropriate investigation?

	Plasma insulin level
	Tissue transglutaminase antibody (TTA) test
	> Plasma glucagon level
	Skin biopsy
	Plasma zinc level

This patient has a diagnosis of a glucagonoma. The polydipsia and polyuria, coupled with the fasting blood glucose result suggest diabetes and the rash is necrolytic migratory erythema a symptom which is the presenting problem in up to 70% of cases of glucagonoma.