Is hypoglycemic polyneuropathy reversible after curative resection of an insulinoma? A case report and literature review.

INTRODUCTION: Insulinoma is a rare neuroendocrine tumor characterized by episodes of hypoglycemia. Peripheral neuropathy associated with hypoglycemia is an uncommon complication of insulinoma, and its reversibility remains a subject of debate within the literature.

CASE REPORT: We describe the case of a 22-year-old female patient diagnosed with a solitary pancreatic insulinoma. The patient experienced recurrent episodes of headache, blurred vision as well as numbness, tingling and burning pain of the limbs over a period of 6 to 12 months prior to definitive diagnosis. Electrophysiological investigations revealed findings consistent with multiple radiculopathies and a motor-predominant axonal sensorimotor polyneuropathy primarily affecting the upper limbs. The biochemical diagnosis of endogenous hyperinsulinemic hypoglycemia was confirmed through a supervised standard 72-hour fasting test. Abdominal computed tomography imaging identified a contrast-enhancing tumor at the pancreatic body-tail transition. The patient underwent a laparoscopic distal pancreatectomy with splenectomy. Postoperative follow-up revealed prompt resolution of hypoglycemia, alongside improvement in dysesthesia and sensory deficit in the extremities as well as most neurophysiological parameters. However, tendon reflexes remained diminished, and subtle distal-predominant lower limb weakness and gait imbalance persisted for several months postoperatively.

DISCUSSION: This case underscores the importance of recognizing a rare neural complication associated with insulinoma. The incomplete resolution of neurological symptoms and neurophysiological abnormalities highlights the potentially lasting impact of recurrent severe hypoglycemia on peripheral neural function.