Insulinoma: Case report and review of the literature

Abstract

Insulinoma is a rare endocrine tumour of the pancreas derived
from ß 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.
There was a favourable clinical evolution, with complete normalization of the clinical symptoms and laboratory.