1 / 12

Emerging Concepts in the Diagnosis and Work-up of Thyroid Cancer

Emerging Concepts in the Diagnosis and Work-up of Thyroid Cancer. APMG Pathologist, MD FCAP. Thyroid Nodules. Found in 4-7% of U.S. adults Approximately 5% are malignant. Fine needle aspiration (FNA) mainstay of diagnosis Bethesda system: Six diagnostic categories

bertha
Download Presentation

Emerging Concepts in the Diagnosis and Work-up of Thyroid Cancer

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Emerging Concepts in the Diagnosis and Work-up of Thyroid Cancer APMG Pathologist, MD FCAP

  2. Thyroid Nodules • Found in 4-7% of U.S. adults • Approximately 5% are malignant. • Fine needle aspiration (FNA) mainstay of diagnosis • Bethesda system: • Six diagnostic categories • Correlate with risk of malignancy and recommended clinical management

  3. Bethesda Diagnostic Categories (2009)

  4. Papillary thyroid carcinoma (PTC) • Approximately 85% of thyroid cancers • Often (50-60%) harbor mutations in BRAF gene • Point mutation at codon 600 results in substitution of glutamate for valine (V600E) • Most common mutation in PTC • Mutation found more often in conventional and tall-cell variants

  5. BRAF V600E mutation leads to constitutive activation of the mitogen activated protein kinase (MAPK) signaling pathway

  6. Atypia of Undetermined Significance • 10-15% of fine needle aspirations (FNAs) • 5-15% risk of malignancy • Often referred for diagnostic thyroidectomy • Low but defined risk of complications

  7. BRAF in diagnosis of PTC • BRAF V600E is VERY SPECIFIC (99.8%) for PTC. • BRAF mutation is very strong evidence of PTC • BRAF V600E is NOT SENSITIVE for PTC (49.5%) • Failure to detect a BRAF mutation does NOT rule out PTC. • Niche for BRAF testing in cases with indeterminate cytology? • BRAF testing can increase the ability of FNA biopsy to reach a diagnosis.

  8. Studies evaluating BRAF in thyroid FNAs

  9. BRAF and PTC prognosis • Numerous studies have found that PTC with mutated BRAF have more aggressive features • Extrathyroidal extension, regional metastasis, etc. • Even applies to small lesions (less than 1.0 cm) • However, excellent prognosis in general for PTC • Over 95% 10-year survival rate • Targeted therapy against BRAF unlikely to markedly improve survival

  10. BRAF testing • Predominantly occurs via PCR • Assay should have the ability to detect the mutation in the background of normal cells seen in the cytology • Can be performed on: • Residual cytology sample in preservative solution after cytological examination • Formalin fixed paraffin embedded tissue blocks and slides

  11. Conclusions • BRAF testing can aid in diagnosing papillary thyroid carcinoma from cytology samples • Particularly useful with indeterminate cytology • Identifies PTC with more aggressive features. • May help identify patients needing surgery. • No current role in therapy selection • Full prognostic significance still unknown

  12. Questions? • Contact pathologist with questions or to request testing on a patient: APMG Pathologist, MD FCAP tlpath@domain.com (888) 555-1212

More Related