TERT RNAscope analysis of papillary thyroid carcinomas ≤1cm and synchronous lymph node metastases.

Introduction: Small papillary thyroid cacinomas measuring ≤ 1 cm usually have a good prognosis, however in a significant number of cases lymph node metastases can be observed. Material: and Methods 22 cases of papillary thyroid carcinomas ≤ 1 cm with synchronous lymph node metastases were examined regarding morphological patterns and immunohistochemical status of p53 and Ki-67. Immunohistochemical BRAF V660E status was examined in primary tumors, whereas TERT alterations in lymph node metastases were evaluated by RNAScope®. Results: Morphological patterns were heterogeneous in both primary tumors and lymph node metastases. Proliferation indices measured by Ki-67 were low. Both primary and lymph node metastases were wild type for p53 by immunohistochemical analysis. No lymph node metastasis showed TERT expression by RNAScope®. Discussion: Our data indicate that TERT aberrations are not involved in the development of early lymph node metastasis in patients with PTC measuring ≤ 1cm.