Neoadjuvant Imatinib Therapy for Gastrointestinal Stromal Tumors Associated With Non-islet Cell Tumor Hypoglycemia (NICTH): A Case Report

Non-islet cell tumor hypoglycemia (NICTH) is a rare paraneoplastic syndrome characterized by insulin-like growth factor-2 (IGF-2) release, often associated with diverse tumor types. Gastrointestinal stromal tumors (GISTs), sarcomatous lesions of the gastrointestinal tract, are rarely associated with NICTH. We present a unique case of a 58-year-old patient diagnosed with a GIST exhibiting recurrent hypoglycemia suggestive of NICTH. Despite normal IGF-2 levels, the IGF-2/IGF-1 ratio supported the NICTH diagnosis, which was confirmed histologically. Imaging revealed a large intraperitoneal mass. Hypoglycemia was managed with high-dose dextrose and hydrocortisone. Treatment with the tyrosine kinase inhibitor, imatinib, was initiated. Surprisingly, imatinib not only reduced the tumor size but also improved hypoglycemia. The study highlights the complexities in managing NICTH and its underlying causes. Current diagnostic limitations, treatment modalities, and unexpected therapeutic responses challenge standard approaches. This emphasizes the need for personalized oncological strategies.