[Histologic and immunohistochemical characterization of medullary thyroid carcinoma]

14 cases of medullary thyroid carcinoma are investigated. The variability of the structure and cell composition of tumors is demonstrated. Stroma amyloidosis is one of the most frequent features of the tumor (83% of cases). The use of immunohistochemistry aiming to show a positive reaction of tumor cells to calcitonin is necessary for diagnosis confirmation. The tumors are found with thyroglobulin-positive cells. One tumor was observed with histologic and immunohistochemical features of mixed medullary-follicular thyroid carcinoma the histogenesis of which needs further studies.