Insulinoma: a propósito de um caso clínico com revisão da literatura Insulinoma: Case report and review of the literature

Insulinoma is a rare endocrine tumour of the pancreas derived from s cells that ectopically secret insulin, which results in hypoglycaemia. The average of occurrence is in persons 40 to 50 years old. The most common symptoms are due to the effect of the hypoglycaemia on the central nervous system. Insulinomas are generally small (≥90% are ≤2 cm), usually not multiple (90%), and only 5 to 15% are malignant. They almost invariably occur only in the pancreas, distributed equally in the pancreatic head, body and tail. Diagnosis relies on clinical features along with laboratory tests and imaging investigations to aid in localization. We report a case of a 57 year old man, who had since his 50 years, episodes of neuroglycopenia, which manifested by dizziness, sweating, headache and confusion. A 72 h fast test, serum levels of insulin and C-peptide strongly suggested insulinoma. Preoperative tumour localization was achieved by means of MRI and selective angiography that revealed a 2 cm nodule in the tail of the pancreas; ultrasonography (US), computed tomography and Octreoscan were not helpful. Surgical resection was performed and splenic vein blood sample showed insulin levels of 5410 mcUI/ml and 186 mcUI/ ml respectively, before and after tumour extraction. Histopathology was consistent with the diagnosis of benign Insulinoma.