Endocrine Abstracts

Introduction: Insulinoma is a rare neuroendocrine tumor. 90% of insulinoma is solitaire and benign, and 10% is malignant. Although seen at any age, it is most commonly noticed in 4th and 6th decades.

Case: A 78-year-old man was referred to a neurology clinic upon a sudden faint, disability to remember and meaningless behavior, and diagnosed with epilepsy in 2008. In 2012, he had a hypoglycemia attack (blood glucose 30 mg/dl) and was referred to Ege University. After consultation, he was hospitalized in order to investigate hypoglycemia etiology. His general status was moderate with BP: 140/80 mmHg and pulse: 78 b.p.m. Other system examinations were normal. His laboratory findings: FBG, 5 mg/dl; HbA1c, 4.9%; cr, 0.71 mg/dl; AST, 18 U/l; and ALT, 9U/l. Dextroz was continued as BG was below 20 mg/dl. The measurements at the time of hypoglycemia: insulin, 17.2 mlU/ml; C-peptide, 2.35 ng/ml; insulin:glucose ratio, 0.66; ACTH, 93.6; cortisol, 21.61 μg/dl; and HGH, 5.23 ng/ml. The clinical and laboratory results suggested insulinoma. The endosonography showed age-related atrophy. His abdominal MR was normal.

In contrast abdominal BT, we found a 3.6×2.3 cm mass lesion associated with neuroendocrine tumor, localized in pancreas tail (Figure 1).

Arterial phase contrast BT

Hypophysis–adrenal axis was normal and PTH: 77.8; therefore, we didn’t suggest MEN.

The patient had a pancreas distal resection.

Pathology report: neuroendocrine tumor well differentiated (Grade I), chromogranin A positive, and cytokeratin 19 positive.

Discussion: Insulinoma is an uncommon pancreatic β cell neoplasm with an incidence of 1/1 000 000. The most frequent symptom is neuroglycopenia, so patients are usually misdiagnosed and referred to psychiatry or neurology clinics. Although endosonography and MR are sensitive methods, they failed to localize insulinoma in our patient because of its place in the tail part of the pancreas. Multiphasic helical BT can detect 2/3 of insulinomas. Here, we aimed to highlight the importance of preoperative insulinoma localization.