Non-islet cell tumor hypoglycemia that required immediate surgery after a long-term asymptomatic state: recommendation for early intervention.

Summary: An 82-year-old woman with a 60-year history of a lung tumor presented with hypoglycemia. Non-islet cell tumor hypoglycemia (NICTH) was suspected; however, her hypoglycemia stabilized with supplemental food. She was discharged, based on her wishes, and planned to undergo surgery later. After discharge, the hypoglycemia worsened rapidly and required immediate resection. Postoperatively, the hypoglycemia resolved. Western immunoblot analysis confirmed the presence of big insulin-like growth factor 2, confirming NICTH. This patient experienced the rapid progression of symptoms after an unprecedentedly long-term asymptomatic state. Therefore, when NICTH is suspected, early intervention is recommended regardless of the presence of asymptomatic state. Learning points: In patients with NICTH, the onset of hypoglycemia is usually within a year of tumor detection, and few reports regarding long-term asymptomatic NICTH have been documented. NICTH can cause rapidly progressive symptoms after a long-term asymptomatic state, as in this case, and an asymptomatic state does not preclude the necessity for intervention, especially when patients are at risk for malnutrition. Tumor resection is the only curative treatment for patients with NICTH, but there is no consensus regarding the timing of surgery. However, considering the possibility of rapid symptom progression, patients should be examined and treated in a timely manner.