January - March 2010, Volume 6, Issue 1

Campos-Olive N, Ferrer-Garcia JC, Safont MJ

Malignant insulinoma in a patient with type 2 diabetes mellitus

Acta Endo (Buc) 2010, 6 (1): 103-109
doi: 10.4183/aeb.2010.103

Insulinoma in a patient with pre-existing diabetes mellitus is very rare.\r\nWe report a case of a malignant insulinoma in a 78-year-old patient with type 2 diabetes mellitus who, after 6 years of insulin treatment, experienced recurrent episodes of\r\nhypoglycaemia, with progressive reduction of dosage to cessation. Endogenous hyperinsulinism was confirmed: glucose 35 mg/dL (74- 106), insulin 23.7 μU/mL (7- 17),\r\nand negative test for sulphonylureas in the plasma. Endoscopic ultrasonography, magnetic resonance and axial computer tomography identified a non-resectable pancreatic tumour, an infiltrating mesenteric vein, as well as metastatic lesions in the liver. After chemoembolization of metastases, initial reduction of hypoglycemic attacks occurred. A few months later, hypoglycaemia recurred, and combined treatment with somatostatin analogs and diazoxide was employed. Although hypoglycemic agents are the commonest\r\ncause of hypoglycemia in type 2 diabetes, insulinomas may occur in these patients. A high degree of suspicion for the presence of an insulinoma should be maintained when\r\nunexplained hypoglycemic episodes occur in a patient with previously stable diabetes despite dose adjustment or cessation of the drugs.

Keywords: Insulinoma, hypoglycaemia, endoscopic US-guided FNAP, somatostatin analogues, controlled fasting test

Correspondence: Juan Carlos Ferrer-Garc?a , Unit of Diabetes, Internal Medicine Department, Consorcio Hospital General Universitario of Valencia, Avda. Tres Cruces, 2, 46014- Valencia, Spain, Tel +34 96 197 20 00 Ext 52007, Fax: +34 96 197 21 31Email: ferrer_juagar@gva.es