Bethesda system for reporting thyroid cytology

BETHESDA THYROID

1. BETHESDA SYSTEM FOR REPORTING THYROID CYTOLOGY Dr .T.Arivazhagan Post Graduate Department Of Pathology

2. Introduction FNA – Essential role in euthyroid patient with thyroid nodule Reduces the rate of unnecessary thyroid surgery patient with benign nodule Only 14% of malignant cases find out by previous FNA practice 50% of malignant cases were find out by new FNA practice

3. Indication Any thyroid swelling Simplest , Easiest & Cheapest way for triage of thyroid lesion Good FNAC & Cell block can diagnose majority of lesions

4. Questions that can be answered Benign vs Malignant Follicular vs Para follicular cell origin Lymphoma vs Carcinoma Primary vs Metastatic tumor Guidance for therapy Type of Surgery Nodal dissection Thyroid vs Parathyroid origin

5. Requisites before FNAC 1. History Age/sex Duration Pain USG findings Thyroid profile Family & Drug history Radiation exposure 2. Clinical examination Size Diffuse/STN/MNG Consistency Fixity 3. Neck nodes

6. Help from radiology really helps Is it thyroid? Solid or Cystic Single or Multiple Size of nodule Circumscribed / Infiltrative Calcification Near by nodes

7. Technique Palpation method Aspiration technique – Ideal in cystic lesion Non aspiration technique ( Only needle is used) USG guided aspiration

8. Sampling Minimum 2 passes Multiple passes – Large swelling Fluid is aspirated – Centrifuge & Smear the sediments Re aspirate after complete evacuation

9. Material aspirated Usually blood mixed scanty material Thick & Thin colloid Viscous,shiny,light yellow, golden colour, brownish Cyst fluid Particulate material – Neoplasm’s

10. Smear interpretation Adequacy Architecture & Cellularity Type of cells & their number / proportion Morphology & Nuclear details Associated features like Colloid , Inflammatory cells & Amyloid History & Clinical details

11. Lymphoid cells in thyroid Hashimoto’s thyroiditis Granulomatous thyroiditis Non specific thyroiditis Riedel’s thyroiditis Grave’s disease Papillary carcinoma Malignant lymphoma

12. Nuclear inclusions Papillary carcinoma Medullary carcinoma Hurthle cell neoplasm Hyalinizing trabecular tumor

13. Fire flare appearance Nodular goiter Grave’s disease Hashimoto’s thyroiditis Follicular carcinoma

14. Squamous cells Thyroglossal cyst Scc Metastatic scc Undifferentiated carcinoma PTC – Metaplastic squamous cells Mucoepidermoid carcinoma

15. Spindle cells Medullary carcinoma Anaplastic carcinoma Spindle epithelial tumor with thymus like differentiation Primary sarcoma Thymoma of thyroid

16. Need of Bethesda Before Non uniform pattern No mention about adequacy Multiplicity of category names After Uniform Unambiguous Plan of management Risk of malignancy

17. Recent Classification NIFTP - NONINVASIVE FOLLICULAR THYROID NEOPLASM WITH PAPILLARY LIKE NUCLEAR FEATURES It comprises of 20-25% of all tumors previously classified as malignancy Has implicated for the risk of malignancy

18. BETHESDA System????Background The terminology of thyroid FNA varied significantly from lab to lab Which creating a great confusion & hindering the meaningful data's To address terminology & other issues related thyroid FNA The National Institute of Cancer NCI thyroid fine needle aspiration state of the science conference Held in Bethesda oct 22 nd , 23 rd on 2007 by Andrea abati

19. Inspiration ? Bethesda system for cervical cytology PAP smear Importance ? Uniform system facilitate effective communication among Cytopathologist Endocrinologist Surgeons Radiologist Also facilitate cytologic-histologic correlation particularly in neoplasm

20. Category Non diagnostic or Unsatisfactory Benign Atypia of undetermined significance or Follicular lesion of undetermined significance Follicular neoplasm or Suspicious for a follicular neoplasm Suspicious for Malignancy Malignant

21. Non diagnostic or Unsatisfactory Criteria Obscuring blood Thick smear Air drying of alcohol fixed smear Inadequate number of follicular cells Adequacy 6 Clusters of follicular cells at least in 2 slides Each group contain at least 10 cells Abundant colloid also consider

22. Nodule Entirely cystic Entirely cystic No worrisome Worrisome Sonographic Sonographic findings findings BENIGN ND or UNS

23. 5 to 10 % consider as ND or UNS Drawback Cystic contents ( macrophages) real problematic Cystic papillary carcinoma cannot ruled out without aspiration of the parenchyma from the nodule Risk of malignancy 1 to 4% Repeat aspiration is recommended

24. BENIGN 60 to 70 % consider as benign Interpretation is essential to avoid unnecessary surgery Benign follicular pattern is most common It includes adenomatoid nodule ,colloid nodule Cells arranged in macro follicles & macro follicular fragments All benign follicular nodules turns into MNG or follicular adenoma Risk of malignancy 0-3% Repeat assessment – by palpation & USG at 6 to 18 months interval

25. 1.Colloid Viscous nature Crackling / folding Chicken wire / mosaic appearance Tendency to surround the follicular cells Occasionally form lacunae 2.Serum Accumulate at the edge of the slide Surrounds blood clots 3.Amyloid Purple/orange Material with embedded fibroblast

26. 1. Lymphocytic thyroiditis Diffuse minimal thyroid enlargement Composed of polymorphic lymphoid cells with thyroid follicular cells L=N --- Blood elements L > N --- LT 2. Granulomatous thyroiditis Painful thyroiditis Associated with viral infections Histiocytes,Granulomas,Multinucleated Giant cell

27. 3.Acute thyroiditis Rare infection – immunocompromised patients Colloid / Follicular cells – Scant/ Absent 4.Riedel thyroiditis Hard fixed mass – mimic malignancy Hypocellular smear 5.Graves disease Usually FNAC not done Colloid with variable follicular cells

28. AUS OR FUS Some case are not easily classified as Benign ,Suspicious or Malignant They referred as AUS or FUS Criteria 1. Smear with sample preparation artifact( air drying artifact , clotting artifact) 2.Prominence of micro follicles in a sparsely cellular aspirate 3.Proportion of micro follicles is less in a cellular smear

29. 4. Predominance of Hurthle cells in a sparsely cellular aspirate with scant colloid 5.Exclusively Hurthle cell smear but clinical setting suggests LT /MNG 6.Focal cytological features of PTC 7.There is an atypical lymphoid infiltrate Assessment of risk of malignancy is difficult because only minority of the cases have surgical follow up.

30. Follicular neoplasm or suspicious for a follicular neoplasm Purpose of this category is to identify a nodule might be follicular carcinoma & triage it for surgical lobectomy FNA is diagnostic in many thyroid carcinoma But it’s a only screening test in follicular thyroid carcinoma

31. Suspicious for follicular neoplasm is preferred because upto 30% cases prove not to be a neoplasm rather than hyperplastic proliferations of follicular cells Majority of FN /SFN turn into FA or adenomatoid nodule than FC

32. Cytology High cellularity Scanty or absent colloid Follicular cells arranged in micro follicular or trabecular pattern Cellular crowding Nuclear atypia & pleomorphism are uncommon Nuclear features of papillary carcinoma are exclude from this category

33. Difference Cat III I’m not certain it’s Negative Don't lose this patient to follow up Malignant risk < 15% Cat IV I’m not certain it’s Positive Consider lobectomy based on the sample Malignant risk > 30%

34. Suspicious for malignancy Most cases in this category belongs to PTC Follicular variant of papillary thyroid carcinoma difficult to distinguish from a benign follicular nodule Criteria Cannot say malignancy if only 1 or 2 features of PTC present Nodules of suspicious for PTC prove 60 to 75 % to be a papillary carcinoma

35. Pattern A ( Patchy Nuclear Changes Pattern) Pattern B ( Incomplete Nuclear Changes Pattern) Pattern C ( Sparsely cellular Pattern) Pattern D ( Cystic Degeneration Pattern)

36. Malignancy The term is used when cytomorphologic features are conclusive for malignancy 3 to 7 % of thyroid FNA’s have conclusive of malignancy especially PTC

37. Papillary carcinoma Cells arranged in papillae Onion skin or cartwheel pattern Enlarged & Crowded Nuclei Oval or Irregular shaped Nuclei Nuclear Grooves Intra Cytoplasmic Pseudo inclusions Pale nuclei with Powdery chromatin Thick nuclear membrane

38. 9. Marginally placed micro nucleoli 10.Psammoma bodies 11. Multinucleated Giant cell 12. Bubblegum like colloid 13. Oncocytic / Hurthle cell metaplasia 14. Squamoid metaplasia 15. Histocytoid cell 16. Hobnail cell

39. Variants of PTC Favorable Classical NIFTP Warthin’s Hurthle cell Cribriform Aggressive Tall cell Columnar cell Diffuse sclerosing Diffuse follicular Solid Trabeculae Hobnail

40. Insular carcinoma Cellular smear Moderate pleomorphism Scant colloid Frequent mitotic activity Necrosis often

41. Anaplastic carcinoma Double check before conforming Variable cellularity Extreme pleomorphism Epithelioid / Spindle shaped / Plasmacytoid Intranuclear pseudo inclusions Neutrophilic infiltration Osteoclast like giant cell

42. Medullary carcinoma Moderate to marked cellularity Predominantly isolated cells Cells are Plasmacytoid / Polygonal / Round Mild to moderate Pleomorphism Rare bizarre Giant cells Salt and pepper chromatin Binucleation is common Inconspicuous nucleoli Granular cytoplasm

43. Diagnostic category 1 st edition 2 nd edition NIFTP reported Cat III 10-30% 6-8% 10-22% Cat IV 25-40% 10-40% 25-30% Cat V 50-75% 45-60% 25-35% Cat IV 97-99% 94-96%

44. Highlights of 2017 BSRTC Original 6 categories remain unchanged Number of enhancements have been introduced in 2017 BSRTC Risk of malignancy recalculated based on post 2010 data Risk of malignancy shown in 2 ways NIFTP – Not considered as malignancy NIFTP - consider as malignancy Usual management of AUS/FLUS & FN/SFN now incorporates the option of molecular testing Definition & Diagnostic criteria for FN/SFN have been revised in light of NIFTP Definition & Diagnostic criteria for PTC is limited to use cases with classical features of PTC