Metastatic Insulinoma: Case Report and Review of the Literature

Abstract

A 64-year-old nondiabetic woman presented with spells of lightheadedness and diaphoresis associated with lethargy and hunger of 2 weeks' duration. Physical examination was unremarkable; however, her fasting plasma glucose was 66 mg/dl, with concurrent plasma insulin of 171 microIU/ml (normal, 5-27 microIU/ml). Her C-peptide and pro-insulin levels were elevated, with negative insulin antibody and negative urinary sulfonylurea levels. Abdominal computed tomographic scan demonstrated a 5 x 4-cm mass in the tail of the pancreas and many liver metastases. She underwent resection of the pancreatic mass, radiofrequency ablation, and cauterization of hepatic lesions. Histology confirmed pancreatic insulinoma. Ten months later, she was free of hypoglycemic symptoms, with normal plasma insulin C-peptide and significantly decreased proinsulin levels. Insulinomas are rare, predominantly benign tumors. Surgery is the only curative treatment. Octreotide can be used to control hormone secretion and tumor growth. Other treatments include hepatic embolization, radiotherapy, chemotherapy, and liver transplantation.

Insulinoma in a patient with type 2 diabetes

“…The patient was treated with intravenous dextrose infusions but continued to have recurrent hypoglycaemic episodes off the infusion. Electrolytes were within the reference range; eGFR was low at 53ml/min/1.73m2 but had been stable over the last few months. Liver function tests showed a low albumin of 23g/L (ref range 35–50) with an elevated alkaline phosphatase level of 196U/L (ref range 30–120).…”

“…Insulinomas are rare pancreatic islet cell tumours occurring in four per million per year 1. They are usually benign, small and solitary, although up to 16% are malignant 2. While most are sporadic, multiple endocrine neoplasia type 1 is present in up to 16% of patients.…”

Insulinoma presenting as refractory seizure disorder

“…Malignant insulinomas are rare, and therefore, little is known about their clinical presentation and long term prognosis. They are generally indolent tumours, and long survival has been reported, even in the presence of liver or lymph node metastases (12,15).…”