The Bethesda System for Thyroid Cytopathology.ppt

Thyroid Bathesda System

1. Dr. Sushant Narayan Mohite.
Guide:Dr.Pooja Naik.

2. Overview
Introduction
Need of uniform reporting system
Format of the Report
Risk of malignancy
Recommended management
Individual categories
Summary

3. Introduction
Role of FNAC of euthyroid patients
Rate of malignancy before & after routine FNA
practice: 14%& 50%
Varied terminologies: confusion> hindering the
sharing of clinically meaningful data among multiple
institutions
“NCI Thyroid Fine Needle Aspiration State of the
Sciecnce Conference”
Preparations for the conference>> 18 months:
permanent web site

4. Introduction
Literature reviews: limited to English language
publications dating back to 1995 using pubmed as
the search engine
First draft of committees’ summary documents
posted on web for online discussion from May 1 to
June 30, 2007
Several subsequent drafts for online discussion:
Revision after each comment period
Organized by Andrea Abati in Bethesda on oct 22
& 23, 2007; 154 registrants including pathologists,
endocrinologists, surgeons, & radiologists

5. Uniform reporting system:
Clarity of communication among cytopathologists,
endocrinologists, surgeons, & radiologists
Terminologies: implied risk of malignancy
Facilitate cytologic-histologic correlation
Facilitate research into epidemiology, molecular
biology, pathology, & diagnosis of thyroid diseases,
particularly neoplasia
Allow easy & reliable sharing of data from different
laboratories for national & international
collaborative studies

6. Format of the Report
Six general diagnostic categories
2 alternative names in some categories
Subcategories: useful & can be informative
Additional descriptive comments beyond sub-
categorizations: optional
Notes & recommendations

8. Risk of malignancy & Recommended management

9. Non-diagnostic or Unsatisfactory
Inadequate samples reported as “non-diagnostic” (ND) or
“unsatisfactory” (UNS)
Adequate No of follicular cells: at least 6 groups of
benign follicular cells each consisting of at least 10
cells
Criteria for ND or UNS
-Obscuring blood
-Overly thick smear
-Air drying of alcohol-fixed smears
-Inadequate No of follicular cells

10. Non-diagnostic or Unsatisfactory
Exceptions to numeric requirements:
-Abundant colloid>macrofollicular
nodule benign
-Any atypia
-Specific diagnosis e.g. lymphocytic
thyroiditis can be rendered
ND or UNS should be limited to less than 10%
excluding samples composed exclusively of
macrophages
Recommendation: USG guided FNA

11. Cyst fluid only (CFO)/Macrophage only
specimen
ND/UNS by some laboratories >cystic PTC could not be
ruled out
Comprises of 15-30%
Some laboratories>↓false –ve result>>benign
NCI: subset of ND/UNS
Risk of malignancy: 4% as compared to 1-4% for other
ND/UNS
USG guided FNA recommended in CFO with worrisome
USG features; diagnostic in 50-88% of cases; some nodule
remain persistently ND/UNS (Excision is considered as
10% prove to be malignant)

12. Cyst fluid only

13. Benign
60-70% of cases
Benign follicular nodule: most common; varying
proportion of colloid & follicular cells in macrofollicles &
macrofollicular fragments
If resected> nodule of multiple nodular goiter or follicular
adenoma
False –ve rate: 0-3%
Recommendation: Repeated assessment by palpation or
USG: 6-18months interval; repeat FNA if suspicious
sonographic changes
Other lists: “consistent with lymphocytis (Hashimoto)
thyroiditis in the proper clinical context” & “consistent
with granulomatous (subacute) thyroiditis”
Other benign conditions: infection, amyloid goitre, black
thyroid, reactive changes, radiation changes, cyst lining
cells

14. Granulomatousthyroiditis

15. Hashimoto’s thyroiditis

16. Atypia of Undetermined Significance (AUS) or
Follicular lesion of Undetermined Significance
Used when FNAs are not easily classified into the
benign, suspicious, or malignant categories
Debated at NCI conference: vote (limited to clinicians)
was taken>majority favor this category

17. Most common scenarios of AUS
Prominent population of microfoliclles not fulfilling
criteria for follicular neoplasm>sparsecellularitywith
scant colloid; cellular smears with disproportionof
microfollicles
Predomiance of Hurthle cells in a sparsely cellular
aspirate with scant colloid
Follicular cell atypia hindered by:
-Air-drying artifacts with slight nuclear
& cytoplasmic enlargements, pale & slightly smudgy
chromatin or mildly irregular nuclear contours
-Clotting artifacts with crowding

18. Most commonscenarios of AUS
Focal features suggestive of PTC in an otherwise
predominantly benign-appearing sample
Cyst lining cellsthat may appear atypical owing to the
presence of nuclear grooves, prominent nucleoli, elongated
nuclei &/or intranuclear cytoplasmic inclusions in an
otherwise predominantly benign-appearing sample
Cellular samplescomposed of exclusive population of
Hurthle cells, yet the clinical setting suggests a benign
Hurthle cell nodule:
-Lymphocytic thyroiditis
-Multinodular goitre

19. Most common scenarios of AUS
Atypical lymphoid infiltrate insufficient for
“suspicious for malignancy”
Minor population of follicular cells show nuclear
enlargement with nucleoli e.g.
-Patient receiving radioactive iodine,
carbimazoleor other drugs
-Repair due to involutional changes
e.g. cystic degeneration &/or hemorrhage

20. Atypia of Undetermined Significance (AUS) or Follicular
lesion of Undetermined Significance
Recognizable benign cellular changes should be
interpreted as AUS
Cellular specimens without significant nuclear or
architectural atypia does not qualify for AUS
AUS results normally obtained in 3-6% of cases: not more
than 7% be reported; higher rates>>overuse
Management: clinical correlation & repeated FNA at an
appropriate interval; clinical follow up or surgery
recommended by some physicians
20% cases>repeatedly AUS
20-25% of resected specimen for AUS> malignancy
Overall risk of malignancy: 5-15%

21. Cytologicdiagnosis of follicular lesion;
simplified

22. Follicular Neoplasm (FN) or Suspicious for a
Follicular Neoplasm (SFN)
Purpose: Identifya nodule that might be a follicular
carcinoma (FC)& triage it to surgical lobectomy
Cytomorphology do not permit difference between FA &
FC; FN/SFN is used instead>lobectomy>definite diagnosis
SFN is preferred by some laboratories: 35% prove to be
hyperplastic proliferations mostly due to multinodular
goiter (MNG)
Majority: FAs & hyperplastic proliferation of MNG
15-30% proved to be malignant: FC/follicular variant of
PTC

23. Follicular Neoplasm (FN) or Suspicious for a
Follicular Neoplasm (SFN)
Cytomorphology: high cellularity with scant to absent
colloid; microfollicles or trabeculae; cellular crowding &
overlapping; larger size
Nuclear atypia & mitoses: uncommon
Minor population of microfollicles can be present
Conspicuous cellularity alone does not qualify for FN
or SFN
Cellular smear with most showing macrofollicles
(intact spheres & flat fragments of evenly spaced
follicular cells)>benign

24. Follicular neoplasm

25. Follicular neoplasm

26. Follicular Neoplasm (FN) or Suspicious for a
Follicular Neoplasm (SFN)
FN/SFN rendered only when majority of follicular cells
are arranged in microfollicles or trabeculae
Cellular samples composed exclusively or (almost
exclusively of) Hurthle cell>Hurthle cell neoplasm: 16-
25% hyperplastic proliferation; 15-45% malignant &
remainder Hurtle cell adenoma

27. Hurthle cell neoplasm

28. Suspicious for Malignancy
Focal & subtle features of malignancy especially in
follicular variant of PTC
Other PTC: incompletely sampled or small No of
abnormal cells
If only 1 or 2 features of PTC are present
Nodules called suspicious for papillary
carcinoma proved to be PTC in 60-75% of cases
after resection
Same principles applied for other malignancies

30. Malignant
Cytomorphology conclusive of malignancy
3-7% of thyroid FNAs have conclusive features of
malignancy
Most common> PTC
+ve predictive valueof a malignant FNA
interpretation: 97-99%

31. Papillary carcinoma of thyroid

32. Papillary carcinoma of thyroid

33. Papillary carcinoma of thyroid

34. Medullary carcinoma of thyroid

35. Summary