Tumors that have been reported to cause NICTH include malignancies associated with insulin receptor antibodies, tumor necrosis factor (TNF), interleukin (IL) -1 or -6; pheochromocytoma associated with excess catecholamine production; and paraneoplastic production of IGF-1 or IGF-2 [2]. This evidence concerns the gene IGF1 and pheochromocytoma.