BACKGROUND: Non-islet cell tumor hypoglycemia (NICTH) is a newly recognized, but uncommon, paraneoplastic syndrome that is associated with tumors of mesenchymal origin. We report a case of NICTH associated with a gastrointestinal stromal tumor (GIST).

CASE REPORT: A 60-year-old man presented to the emergency department of our hospital after being found unconscious in his home. His serum blood glucose on hospital admission was 40 mg/dL. He reported a three-month history of diffuse abdominal pain, fatigue, and blurred vision. Laboratory medicine investigations showed reduced levels of insulin, C-peptide, insulin-like growth factor binding protein (IGFBP)-3, and insulin-like growth factor (IGF)-1, but his IGFBP-2 was increased. Computed tomography (CT) scan of the chest and abdomen showed an abdominal mass that involved the small bowel, mesentery, and omentum, with lesions in the right lung and the left rib. Histopathology of a CT-guided biopsy of the abdominal mass showed a low-grade sarcomatous spindle cell neoplasm that was positive for CD117 using immunohistochemistry and with an exon 11 c-KIT mutation. These findings were consistent with a diagnosis of GIST and treatment with imatinib commenced.

CONCLUSIONS: This case report has shown that hypoglycemia in the setting of low levels of insulin, C-peptide, IGF-1, and IGFBP-3 is suggestive of a diagnosis of NICTH, which should be investigated for an underlying source, which in this case, was confirmed to be a malignant GIST.

Keywords: gastrointestinal stromal tumors, Hypoglycemia, Paraneoplastic Syndromes, Proto-Oncogene Proteins c-kit