Neuroendocrine Tumor of Unknown Primary Origin with Liver Metastasis Leading to Nonislet Cell Tumor Hypoglycemia

We describe a case of a 32-year-old nondiabetic lady who presented to our hospital with episodes of recurrent hypoglycemia. Investigations revealed suppressed insulin-like growth factor-1 (IGF-1) and elevated IGF-2 to IGF-1 ratio in the absence of hyperinsulinemia, which favored a diagnosis of nonislet cell tumor hypoglycemia (NICTH). Imaging revealed multiple lesions in the liver and a mesenteric nodal mass. Liver biopsy was suggestive of metastatic well-differentiated neuroendocrine tumor (NET) [World Health Organization (WHO) grade 3]. Our patient had a fairly aggressive progression of disease. She was given chemotherapy for the tumor, but the anatomic site of the primary malignancy could not be determined despite extensive imaging and diagnostic workup. This case highlights NICTH, which is a rarely encountered but life-threatening cause of hypoglycemia, and underlines the importance of tumor localization for effective treatment.