CCH - C-cell hyperplasia. MTC - medullary thyroid cancer. *Local tumor stage according to UICC 2010 - pT1a ≤ 10 mm; pT1b = 11 - 20 mm; pT2 = 21 - 40 mm; pT3 > 40 mm or any size with with extrathyroidal extension; pT4 = moderately advanced or very advanced disease. Meta - lymph node metastasis: N1a - central lymph node metastasis, N1b - lateral lymph node metastasis. Dist Meta - distant metastasis. RET mutation - mutation in the rearranged during transfection (RET) proto-oncogene, found after diagnosis of MTC. The gene discussed is RET; the disease is metastatic malignant neoplasm in the lymph nodes.