Endocrine Abstracts

Introduction: Insulinoma is a rare form of a functional neuroendocrine tumor with an estimated incidence at 1–2 new cases per million persons per year. This infrequent endocrinopathy, frequently escaping standard disease course, constitutes a diagnostic challenge for every endocrinologist. Successful surgical resection of the lesion is the only available method that ensures patient’s full recovery.

Case study: 53 years old patient with complaints about recurring episodes of hypoglycemia, without accompanying adrenergic symptoms though, was admitted to Department and Clinic of Endocrinology, Medical University of Lublin. During diagnostic procedures: low glucose levels (ranging from 1.94–3.56 mmol/l) with corresponding inadequately high insulin levels were observed in a prolonged glucose tolerance test, where glucose and insulin concentrations measurements had been carried out every hour. Afterwards supervised 72-h fast was introduced, only to be terminated after just 24 h, due to symptomatic hypoglycemia (2.28 mmol/l). Insulin levels at the end of fasting remained disproportionately elevated (10.7 mU/l). Based on follow up diagnostic tests we were able to exclude other potential causes of hypoglycemia in the form of adrenal insufficiency and hypothyroidism. Abdomen CT scan didn’t reveal any lesions in pancreas whereas abdomen MRI unveiled presence of the tumor, 2 cm in diameter, located in the tail of pancreas. On the 1st of September 2016 patient underwent surgical resection of the pancreas mass. Histologic evaluation confirmed the diagnosis of insulinoma (pNET: G2 insulinoma). Octreoscan and abdomen MRI didn’t indicate a diffuse process. Currently all of the symptoms subsided, the patient doesn’t require any additional treatment.

Conclusions: Insulinomas are neuroendocrine tumors of rare occurrence. The readily available imaging methods rarely allow for a location confirmed diagnosis because of borderline small size of lesions. Persistent hypoglycemia being the most characteristic symptom facilitates the diagnosis and introduction of proper treatment.