MOLECULAR MARKERS FOR LYMPH NODE METASTASIS IN PAPILLARY CARCINOMAS <1CM (PTMC)

AUTHORS:
M. Eich (Berlin, Germany) , C. Chiapponi (Cologne, Germany) , A. Schultheis (Cologne, Germany)
Background:
The clinical significance of papillary carcinomas <1cm (PTMC) is increasingly being questioned. Nevertheless, PTMCs with nodal metastases (N+) are seen in clinical practice. In the present study possible molecular markers for identifying N+ PTMC were searched.
Methods:
N+ PTMCs were retrospectively identified. In primary tumors and in their lymph node metastases morphological patterns as well as immunhistochemical expression of BRAF, p53 and Ki67 were analyzed. TERT expression was examined by TERT RNAscope® in-situ hybridization.
Results:
Primary tumors were in average 0.52 (± 0.27) cm large and in 13 (59%) cases multifocal. Nodal metastases were in average 1.64 cm large (range 0.2mm-4.5cm) and cystic in 14 (63.3%) cases. 6 (27,2%) primary tumors displayed a follicular and 16 (72.7%) a classical variant. Five (22.7%) of them included both subtypes with discrepancy between primary tumor and nodal metastasis. Desmoplasia was seen in 16 (72.7%) primary tumors and in 14 (63.3%) nodal metastases. BRAF was positive in 14 (63.3%) tumors. Ki67 ranged from 0.05 to 2.69% in primary and from 0.22 to 2.56% in lymph node metastases. p53 and TERT were negative all in all tumors.
Conclusions:
p53, Ki67 and TERT are no suitable markers for detecting metastatic PTMCs. Further studies are required in order to identify markers of lymph node metastasis in PTMC.