A Case of Proinsulin-Secreting Malignant Insulinoma in an Elderly Patient with Cerebral Infarction

Abstract

The diagnosis of insulinoma is sometimes challenging and the symptoms of hypoglycemia may be overlooked in elderly patients with cerebrovascular diseases and higher cerebral dysfunction. Recently, there have been an increasing number of case reports of insulinoma secreting proinsulin without hyperinsulinemia. We report a case of proinsulinsecreting malignant insulinoma in a 72-year-old man with aphasia due to cerebral infarction. He manifested no apparent symptoms, although he was incidentally found to have recurrent hypoglycemia by plasma glucose measurements. The Fajans, Grunt and Turner indexes were all within normal range and the arterial stimulation and venous sampling (ASVS) test revealed no increase in insulin concentration. However, proinsulin concentration was markedly elevated (2470 pmol/l) and well-differentiated endocrine adenocarcinoma, malignant insulinoma, with 2 cm in size in the tail of the pancreas was surgically removed. The diagnosis of hypoglycemia requires careful attention especially in elderly persons and/or patients with cerebrovascular diseases. Measurement of proinsulin is recommended in the diagnosis of insulinoma without hyperinsulinemia.

Role of Diabetes in prevalence of Tuberculosis

“…Diabetes is one of the most important public health challenges for the 21 st century [42]. Diabetes mellitus is associated with an increased risk for a number of serious and sometimes life-threatening diseases like cardiovascular disease [43,44], peripheral vascular disease, and cerebrovascular disease [45,46]. The high blood sugar level produces some of the symptoms of polyuria (frequent urination), polydipsia (increased thirst) and polyphagia (increased hunger) [47].…”

Late Stage Complications of Diabetes and Insulin Resistance

“…Changes in the normal glucose levels [31] in blood will lead to abnormal physiological states causing either hypoglycemia (low glucose levels) or hyperglycemia (high glucose levels). Low blood glucose or hypoglycemia [32] is the most common immediate health problem for patients with diabetes. It occurs when the body gets too much insulin, too little food, a delayed meal, or more than the usual amount of exercise.…”

Biomarkers of Internal Origin and Their Significance in Diabetes and Diabetic Complications

“…The Insulin itself in its zymogen form (Proinsulin) is a marker for diagnosis of insulinoma without hyperinsulinemia [49]. Patients with type 1 diabetes found to have lower serum osteocalcin, which results in a decreased activity of osteoblasts.…”