IGF2 and neoplasm: There is no international standard for the diagnosis of NICTH, in view of the fact that most of the previous reports[21] have the following characteristics: 1 recurrent hypoglycemia usually occurs during fasting and at night; 2 the tumor volume is usually large,[22] which is more common in middle-aged and elderly people; 3 the levels of insulin and C-peptide were low; and 4 IGF-II levels may or may not increase.