An observational analysis of insulinoma from a single institution

Insulinoma is the commonest functioning pancreatic neuroendocrine tumor causing hyperinsulinemic hypoglycemia.

This study is aimed to evaluate the clinical features, preoperative laboratory and imaging diagnosis and pathologic findings of insulinoma.

Data of the patients from 2001 to 2016 diagnosed as insulinoma in Tongji Hospital, China were retrospectively extracted and analyzed.

A total of 40 patients were diagnosed as insulinoma with a male/female ratio of 0.68:1. The median onset age was 46.5 years. Nearly all the included patients presented neurological symptoms and 60% presented autonomic symptoms. More than 95% of the patients met the functional European Neuroendocrine Tumor Society criteria including glucose, insulin and C-peptide levels. The preoperative detection rates of ultrasonography, enhanced computed tomography, magnetic resonance imaging, and endoscopic ultrasonography were 60.50%, 84.95%, 80% and 83.3% respectively. The joint imaging examinations can markedly increase the detection rate. The mean tumor size was 1.89 ± 0.72 cm. Ki-67 index by histopathological diagnosis were all less than 20%. The positive rates of insulin, synaptophysin and chromogranin A were close to 100%.

Laboratory tests of glucose, insulin and C-peptide are reliable for preoperative diagnosis. Combination of the imaging examinations can improve the diagnosis.