Abstract
The delayed diagnosis of insulinoma remains a clinical issue. One of the main causes of such a delay is hypoglycemia unawareness. A 53-year-old woman fell unconscious during postprandial exercises. Flash glucose monitoring (FGM) systems revealed glucose profiles with fasting hypoglycemia, which facilitated the clinical diagnosis of insulinoma even though she was unaware of her hypoglycemia. The preoperative comparison of the blood glucose values provided by FGM with those obtained from capillary blood were consistent. Thus, FGM may have potential utility in revealing the presence of insulinoma-induced hypoglycemia.