FNA needle rinses preserved in Cytolyt are acceptable specimen type for mutation testing of thyroid nodules

IntroductionThis study investigated the application of molecular testing to residual thyroid fine-needle aspiration material from needle rinses collected in Cytolyt.Materials and methodsTwo thyroid needle rinses from 135 patients were collected in Cytolyt during routine diagnostic workup in our institution. Molecular testing was performed to detect 14 genetic alterations in BRAF, K-, H-, N-RAS genes as well as RET/PTC1, RET/PTC3, and PAX8/PPARγ and verified by next generation sequencing and correlated with cytologic diagnoses.ResultsMolecular testing revealed a total of 17 mutations across specimens with benign nodule (n = 5; HRAS, NRAS), Hürthle cell neoplasm (n = 2; BRAF, HRAS) and Papillary thyroid carcinoma (n = 10, 9 BRAF, 1 KRAS) cytology. No RNA gene rearrangements were detected.ConclusionsMutations and translocations associated with thyroid cancer can be detected in thyroid fine-needle aspiration needle rinses preserved in Cytolyt specimens collected during routine patient management, which are typically discarded when a diagnosis is attained.