Aims: The molecular alterations underlying follicular Hürthle cell carcinomas (FHCCs) are largely unknown. In an attempt to clarify this issue, we analysed a series of Hürthle cell tumours for the presence of RET/PTC and PAX8/PPARG rearrangements and BRAF, HRAS and NRAS mutations. Methods and results: We investigated a series of 20 follicular Hürthle cell tumours [17 FHCCs and three follicular Hürthle cell adenomas (FHCAs)]. RET/PTC rearrangements were found in 33% of FHCAs and in 38% of FHCCs. All RET/PTC-positive FHCCs had a solid pattern of growth. PAX8/PPARG rearrangement was present in 27% of the FHCCs which displayed, in most cases, a follicular architecture. NRAS mutation was detected in one FHCC. An FHCC with a solid/microfollicular growth pattern scored positive for both RET/PTC and PAX8/PPARG rearrangement. Conclusions: Our study has shown a significant association between RET/PTC rearrangements and FHCCs with a solid growth pattern, thus raising the possibility of using tyrosine kinase inhibitors for the treatment of patients with FHCCs, which are often refractory to radioiodine treatment.

Follicular carcinoma, Genetics, Hürthle, RET/PTC, Thyroid,
Department of Clinical Genetics

de Vries, M.M, Celestino, R, Castro, P, Eloy, C, Máximo, V, van der Wal, J.E, … Soares, P. (2012). RET/PTC rearrangement is prevalent in follicular Hürthle cell carcinomas. Histopathology, 61(5), 833–843. doi:10.1111/j.1365-2559.2012.04276.x