Symptomatic Pancreatic Insulinoma Successfully Treated With Alcohol Ablation

Abstract

Introduction: Insulinomas are the most common type of functional pancreatic endocrine tumor. Representing 1-2% of all pancreatic neoplasms, these insulin secreting tumors occur in approximately 4 out of 1 million people per year. Insulinomas are characterized clinically by fasting hypoglycemia, neuroglycopenic symptoms, and occasionally, sympathoadrenal autonomic symptoms. Currently, surgical resection is the mainstay of therapy; however, in elderly patients with comorbidities, a more optimal alternative is needed. An 81-year-old woman presented with symptomatic and persistent hypoglycemia despite administration of IV glucose. Laboratory testing revealed elevated proinsulin, insulin, and c-peptide levels, consistent with insulinoma. A helical CT scan with IV contrast showed a 1.1 cm hyperdensity in the superior aspect of the body of the pancreas. Linear array EUS demonstrated a round, well demarcated, hypoechoic lesion measuring 1 cm x 1 cm in the neck of the pancreas. Cytology was obtained by EUS guided FNA which revealed numerous monomorphic appearing epithelial cells singly and in loose clusters. Findings were consistent with a pancreatic epithelial neoplasm, possibly a pancreatic neuroendocrine tumor. Patient was deemed a poor surgical candidate due to her significant cardiovascular disease. Therefore, alternative therapy with alcohol ablation was recommended. A total of 1 ml of 98% alcohol was injected under EUS guidance during a single session with adequate tissue transformation from hypoechoic to echorich. There were no complications during or after the procedure. Following alcohol ablation, serum insulin normalized and IV glucose was discontinued on post-ablation day 2. She was discharged on day 7. To date, clinical follow-up for more than 14 months with our facility as well as a local endocrinologist has shown no symptom recurrence and euglycemia. Endoscopic ultrasonography is an optimal diagnostic modality for identification of insulinoma. Surgical enucleation or resection is currently considered the therapeutic standard for treatment of insulinomas and has a high success rate. In elderly patients with comorbidities; however, this mainstay of therapy can be associated with high morbidity and mortality rates. In this particular subset of patients, alternative therapy with minimally invasive EUS guided ablative treatment may be a more optimal alternative. Currently, there have only been a few cases of EUS guided ablation of insulinomas reported. Cases varied by technique and extent of post-procedural complications. To our knowledge, this is the first case of EUS guided alcohol ablation of a solitary insulinoma performed in a single treatment session with no complications reported in the United States.