Neoplasms Causing Nonhyperinsulinemic Hypoglycemia

Non-islet cell tumor hypoglycemia (NICTH) is uncommon. Many of the tumors associated with NICTH are mesenchymal tumors, although carcinomas are also involved in some cases. High serum levels of insulin-like growth factor II (IGF-II) have been associated with NICTH. Analysis of 4 pituitary tumors, 2 adrenocortical tumors, 42 solitary fibrous tumors, and 23 other mesenchymal tumors for IGF-II protein and mRNA showed that most mesenchymal tumors expressed IGF-II protein and mRNA, although only 4 of 48 patients had associated hypoglycemia. Tumor size was related to IGF-II production. Tumors less than 5 cm were usually negative for IGF-II mRNA, whereas 92.3% of tumors greater than 9 cm were positive for IGF-II mRNA. These results show that IGF-II mRNA and protein can be readily detected in many tumors, even when the tumors are not associated with clinical hypoglycemia. The expression and production of this growth factor cannot accurately predict patients with clinical evidence of hypoglycemia.