The concomitant occurrence of autoimmune thyroid diseases [Hashimoto’s thyroiditis (HT) and Graves’ disease], and thyroid neuroendocrine tumours and other neoplasms (C-cell hyperplasia, medullary thyroid cancer, papillary thyroid cancer and neurofibroma) with NF1 has been reported in previous studies (4,9,10,11,12,13). Here, NF1 is linked to hematocrit.