EP104 – Slide Micro-Dissection Extracted Nucleic Acid Molecular Marker Testing from Bethesda Iii Slides: A Case

      Guttler, Richard1 1 International Thyroid Center, Santa Monica Thyroid, Santa Monica, California, USA   Background: Common for thyroid biopsies to be done without backup molecular markers in case of a Bethesda III result. It may be necessary to repeat the biopsy to collect the markers. A case with Bethesda III cytology using the slides from an earlier biopsy for slide Micro-dissection Extraction for nucleic acid is presented. Methods: 73 Y/O F with history of Hashimoto’s for second opinion with enlarging goiter, bilateral vocal cord weakness and very elevated thyroglobulin at 3900 ng/ml. FNA was reclassified as Bethesda III. We enlisted a lab ( Interpace Diagnostics ). to do the testing on her original biopsy slides. Results: She was advised to have surgery. Surgery 120 gram Hashimoto’s Goiter no cancer. Discussion: KRAS in a benign goiter. However the classifier was benign.Molecular marker and classifier obtained from slides by this new technology can be of great help if prior biopsy material is suitable for testing and for those who do not collect needle washout sample to hold for testing if the result is Bethesda III or IV. However liquid based biopsy samples are not suitable for this procedure.The test is available from several commercial labs at present. Conclusion: 1. Prior biopsy slides can be tested for molecular markers and classifier by this new technique. 2. If this method becomes universally available for clinical practice it can reduce the number of repeat biopsies to obtain molecular markers. 3. Liquid based thyroid biopsy samples are not suitable for testing at present. 4. This will reduce the patient’s anxiety from another biopsy.   References:
    1. Beaudenon-Huibregtse et al  Centralized molecular testing for Oncogenic gene mutations  Thyroid 2014 Oct 24 (10): 1479-87 Labourier et al   Molecular testing for miRNA, mRNA and DNA on fine needle aspiration improves the preoperative diagnosis of thyroid nodules   JCEM 2015, 100: 2743.
    2. Wylie et al   Molecular classification of thyroid nodules by combined testing for miRNA gene expression and somatic gene mutations   Journal of Pathology  2016 Feb 8;2(2):93-103.
    3. Shifrin et al  Mutational analysis of metastatic lymph nodes from papillary thyroid cancer  Surgery. 2017 Jan;161(1):176-187


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