05/07/2018 1 Maastricht Pathology 2018 June 19-22 Maastricht The Netherlands Thyroid Cytology in the MDT setting R.Dina MD, FIAC, FRCPath Dept of Histopathology Hammersmith Hospital Thyroid Cancer Introduction ¤ The incidence of thyroid cancer appears to be increasing slowly. ¤ In the period 1971-1995 the annual UK incidence was reported at 2.3 per 100,000 women and 0.9 per 100,000 men, with approximately 900 new cases and 250 deaths recorded in England and Wales due to thyroid cancer every year. ¤ In 2006 data from Cancer Research UK reported 1,933 new cases in the UK, with an annual incidence of 4.4 per 100,000 women and 1.6 per 100,000 men. Thyroid cancer is the commonest malignant endocrine tumour, but represents only about 1% of all malignancies.
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05/07/2018
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Maastricht Pathology 2018June 19-22 Maastricht
The Netherlands
Thyroid Cytology in the MDT
setting
R.Dina MD, FIAC, FRCPathDept of HistopathologyHammersmith Hospital
Thyroid CancerIntroduction
♦ The incidence of thyroid cancer appears to be increasing slowly.
♦ In the period 1971-1995 the annual UK incidence was reported at 2.3 per 100,000 women and 0.9 per 100,000 men, with approximately 900 new cases and 250 deaths recorded in England and Wales due to thyroid cancer every year.
♦ In 2006 data from Cancer Research UK reported 1,933 new cases in the UK, with an annual incidence of 4.4 per 100,000 women and 1.6 per 100,000 men. Thyroid cancer is the commonest malignant endocrine tumour, but represents only about 1% of all malignancies.
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Thyroid Cancer
♦ 5-10% of the adult population develop a palpable thyroid nodule
♦ 5% of nodules are malignant
♦ Increasing in incidence?(increased sensitivity of tests and the higher detection rate, rather than a true change in incidence)
CLINICAL PATHWAYPRIMARY CARE:URGENT REFERRAL
♦ Symptomatic patient GPGPs may wish to arrange blood tests for TFTs, Corrected Calcium - but should not wait for the results before
making a referral if an urgent referral is indicated as set out below:
♦ All patients with Thyroid Swellings and any of:
Enlarging thyroid lumpThyroid lump in patient >65 or<18 years of agePrevious neck irradiationAssociated cervical lymphadenopathyVoice change / hoarsenessFamily history thyroid cancer
Thyroid Swelling AND Stridor
Referral to the Regional Thyroid MDT is required for all
patients with
♦ • Newly diagnosed thyroid cancer (Thy5) or suspicious thyroid cancer (Thy4) on FNA cytology.
♦ • Atypical follicular/equivocal cytology (Thy3)
♦ • Histological diagnoses of thyroid cancer
♦ • Patients with inherited thyroid cancer syndromes
♦ • Recurrent Cancer♦ • All Paediatric Thyroid Lumps
♦ The Thy classification adopted by the Royal College of Physicians (http://www.british-thyroid-association.org/Guidelines/)
� Thy1: Non-diagnostic (inadequate or where technical artefact precludes interpretation; smears must contain 6 or more groups of at least 10 thyroid follicular cells to be considered adequate).Thy2: Non-neoplastic (features consistent with a nodular goitre or thyroiditis or cysts).Thy3 (i): All follicular lesions.(ii): There may be a very small number of cases where the cytological findings warrant inclusion in this category rather than Thy2 or Thy4. This will be indicated in the report.Thy4: Abnormal, suspicious of malignancy (suspicious, but not diagnostic, of papillary, medullary or anaplastic carcinoma or of lymphoma).Thy5: Diagnostic of malignancy (unequivocal features of papillary, medullary or anaplastic carcinoma, or of lymphoma or of metastatic tumour).
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The Thy classification adopted by the Royal College of Physicians
♦ Blood only♦ Only few bare nuclei
without evidence of origin from a cyst (macrophages colloid,fluid)
♦ Technical artefacts
� Thy1: Non-diagnostic (inadequate or where technical artefact precludes interpretation; smears must contain 6 or more groups of at least 10 thyroid follicular cells to be considered adequate).Action: FNAC should be repeated with or without ultrasound guidance.
Diagnostic pitfalls
♦ Adequacy of material (skills of the aspirator, cellularity of the lesion and target)
♦ Overlapping morphologic features
Thyroid cytology coming from other Institutions
♦ First pass(es): conventional smears (alcohol and air dried (1:1)
♦ Rest of material: LBC
♦ Rationale: avoid excessive No of blood stained smears
Unsatisfactory rate♦ With experience, the average
“unsatisfactory” rate is about 5% to 10%. It is incorrect to consider unsatisfactory or non diagnostic tests as negative.
♦ The lowest rate will be achieved by close cooperation between the clinician and the cytopathologist, with immediate assessment of material (Clinical Departments must allocate resources to Pathology!)
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Criteria of Adequacy♦ At least 6 groups of
follicular cells, each with approx. 10 cells
♦ Risk of malignancy is similar to diagnostic, benign samples (Thy2)
Unsatisfactory rate♦ The number of inadequates appears to be directly
related to the immediate assessment by a cytologist rather than by a clinician or a cytopathologist performing the procedure, experience being a more important determinant in the success of a thyroid FNA (3).
♦ Nasuti JF, Gupta PK, Baloch ZW. Diagnostic value and cost-effectiveness of on-site evaluation of fine-needle aspiration specimens: review of 5,688 cases.Diagn Cytopathol. 2002 Jul;27(1):1-4
Crucial factors in the interpretation of scanty cellular FNAs
♦ The availability of complete clinical information as more often clinically benign lesions are the ones which yield fewer cells.
♦ Identification of background colloid ♦ Bare thyroid nuclei (not lymphocytes!)♦ Pigmented macrophages
How to improve♦ The nonaspiration technique and use of smaller
needles (25 g) has been advocated to reduce blood contamination
♦ It probably decreases the incidence of WHAFFTs♦ Cell blocks prepared from FNA biopsies have also
been advocated to increase diagnostic accuracy .
♦ Kamal MM, Arjune DG, Kulkami HR. Comparative study of fine needle aspiration and fine needle capillary sampling of thyroid lesions.Acta Cytol. 2002 Jan-Feb;46(1):30-4.
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Baskin HJ. Ultrasound-guided fine-needle aspiration biopsy of thyroid nodules and multinodular goiters. Endocr Pract. 2004 May-Jun;10(3):242-245.
♦ Analysis of inconclusive fine-needle aspiration of thyroid follicular lesions suggests a malignancy rate of 2.2%, which is no worse than patients with a benign preoperative diagnosis.
♦ A balanced approach with careful follow-up for nondiagnostic cytology is prudent
The Thy classification adopted by the Royal College of Physicians
� Thy2: Non-neoplastic (features consistent with a nodular goitre or thyroiditis).Action: Two diagnostic benign results 3-6 months apart required to exclude neoplasia. Decision to intervene surgically dependent on clinical factors (e.g. clinical suspicion and the presence of manifestations causing physical or psychological distress i.e. breathing difficulties or unfavourable cosmetic appearance).
The Thy classification adopted by the Royal College of Physicians
� Thy3 (i): All follicular lesions.Action: Lobectomy. Complete thyroidectomy will be necessary if histology proves malignant.(ii): There may be a very small number of cases where the cytological findings warrant inclusion in this category rather than Thy2 or Thy4. This will be indicated in the report.Action: Discuss with cytopathologist to determine course of action.
♦Thy3a: cytological/nuclear or architectural atypia, or other features that raise the possibility of neoplasia, but which are insufficient to enable confident placement into any other category.
Thy3 a and Thy3f subcategories
The Thy classification adopted by the Royal College of Physicians
♦ Thy4: Abnormal, suspicious of malignancy (suspicious, but not diagnostic, of papillary, medullary or anaplastic carcinoma or of lymphoma).Action: Surgical intervention indicated for differentiated tumour. Further treatment dependent upon pathology report. For lymphoma, metastatic tumour or undifferentiated i.e. anaplastic thyroid carcinoma, further investigation indicated.
H.R. 19-05-08
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♦ Highly cellular aspirate containing numerous clusters and sheets of follicular cells showing nuclear crowding;
♦ Nuclear grooving and pseudoinclusions are occasionally identified
♦ The epithelial fragments are seen within a background of moderate fluid colloid and mixed inflammatory cells.Therefore this is a Thy 4
The Thy classification adopted by the Royal College of Physicians
♦ Thy5: Diagnostic of malignancy (unequivocal features of papillary, medullary or anaplastic carcinoma, or of lymphoma or of metastatic tumour).Action: Surgical intervention indicated for differentiated thyroid cancer, depending on tumour size, clinical stage and other risk factors such as gender and extremes of age. Appropriate further investigation indicated alongside radiotherapy/chemotherapy for anaplastic carcinoma, lymphoma or metastatic tumor.
What are the proportions of patients in each Thy classification?
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The distribution of Thy categories in 2014
Histology 118
Which are the factors that may influence cyto-histo correlations?• The operator• The cytopathologist• The MDT
Reproducibility of Thy3 category in FNA of the Thyroid and the effect of MDT discussion on the management of Thy3 cases in a Multilaboratory setting
Thy1, 9%
Thy2, 75%
Thy3, 9%
Thy4, 3% Thy5, 4%
Total=2157
All Thy3-5 cases were discussed at the Central MDTMeeting, although the two labs (HH and SMH) were still independently reporting.The guidelines followed were the same.
♦ 50% of false negatives are associated with incidental microcarcinoma
♦ 25% are “true” false negatives (no cytological criteria of suspicion or malignancy)
♦ 17.5% are sampling errors (not representative of the nodule)
♦ 7.5% is an interpretation error
Progress in Identifying Driver Mutations in Thyroid Cancer
Ref Nikiforov et al 2015
The Cancer Genome Atlas Project
• Proposes “a reclassification of thyroid cancers into molecular subtypes that better reflect their underlying signalling and differentiation properties, which has the potential to improve their pathological classification andbetter inform the management of the disease”.
Our study• Large number of point mutations seen in BRAF gene but the most
common one is the T → A transversion at base 1799 of exon 15 (valine to glutamic acid at position 600)
• This transversion is an important oncogenic mutation in PTC and occurs roughly in 45% of cases
• A molecular diagnostic test for the BRAF Val600Glu mutation could help improve accuracy in difficult to determine thyroid nodules
• Aim: compare Sanger sequencing, pyrosequencing and next generation sequencing for the detection of the BRAF Val600Glu mutation
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Discussion (1)• Molecular testing is nowadays becoming a routine approach for
the diagnosis of several disorders and the identification of biomarkers an integral tool in patients’ management
• Quality and quantity of material isolated from diagnostic samples is of vital importance.
• In this study, the frequency and the amount of DNA extracted from LBC-FNAs was consistently higher than that of smear-FNAs. However the quality of the material was equally comparable as shown by the complete concordance in results irrespective of the origin of DNA
• From our study we would recommend that LBC-FNAs, if available, are preferably used for molecular testing because DNA
Advantages, disadvantages and cost analysis of Sanger sequencing, pyrosequencing and Next Generation Sequencing in our lab
EC: equipment cost; PT: personnel time; CPS: cost per sample; 1: Applied Biosystem’s 3130 sequence analyser; 2: Applied Biosystem’s 3500xL sequence analyser; 3: includes cost of PCR reaction
Discussion (3)• The British Thyroid Association has produced draft guidance on
differentiated thyroid cancer that includes discussion of BRAF p.Val600Glu testing in thyroid FNA cytology, stating that “molecular analysis (e.g. BRAF p.Val600Glu mutation for PTC, alone or as part of a panel) is an emerging field and may refine the prediction of both benignity and malignancy in thyroid cytology samples”
• Overall NGS can detect other mutations that a single gene analysis does not provide.
• NGS may in the future provide a plethora of additional information and a more comprehensive set of data to guide treatment choice in the context of personalised medicine.
From Darkness into Light
No molecular marker Many molecular markersOne molecular marker
Follicular lesions♦ The morphological distinction of
hyperplastic adenomatous nodules, well-differentiated follicular carcinomas, and follicular variants of papillary carcinoma is difficult, even for cytologists with extensive experience of thyroid fine needle aspiration.
♦ Attempts to improve the preoperative diagnosis of thyroid nodules by use of strict instructions for obtaining adequate specimens and inclusion of' clinical characteristics (such as sex, dimcnsion of' thc nodule, character of the gland by palpation) have been reported.
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Granulomatous Thyroiditis (De Quervain-Subacute)♦ Follicular cells with
cells arranged perpendicularly to metachromatic material
Papillary Carcinoma:A Cytologic Diagnosis
♦ Architecture irrelevant– Papillary, Follicular, Mixed, Solid , Cystic– Diffuse sclerosis variant is hard to recognize
♦ Psammoma bodies are rare♦ Invasion not a criterion
– Encapsulated variant♦ Nuclear features predict behavior
Papillary Carcinoma
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Cytologic Features ofPapillary Carcinoma
♦ Crowded overlapping nuclei
♦ Irregular nuclear membrane
♦ Nuclear grooves♦ Pale vacuolated
nucleoplasm♦ Peripheral margination
of chromatin♦ Nuclear
pseudoinclusions
Thy 5, papillary carcinoma
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Pitfalls♦ Pseudoinclusions can
be mimicked by red blood cells overlying nuclei or by air bubbles ( which however normally involve both cytoplasm and nucleus)
Pitfalls in thyroid tumour pathologyJ Rosai, E Kuhn, ML CarcangiuHistopathology 2006 (Aug)49:107-120
Medullary Carcinoma♦ Plasmacytoid and /or
spindle cells♦ Cytoplasm granularity♦ Usually dispersed but
also trabecular or follicular pattern
♦ positive with calcitonin
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Colloid in LBC and conventional smears
Nuclei in LBC and conventional smears
Nuclear Pseudoinclusons and membrane irregularity
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Papillary carcinoma in LBC
♦ Nuclear pseudoinclusions and membrane irregularity are equally identifiable in LBC albeit hyperchromatism is usually more prominent
www.eurocytology.eu/ecc2018
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RCPath Part 2 examination♦ 8 non-gynae cytology cases in pairs in 20’ slots; the cases
are marked centrally according to a predetermined scoring system
♦ 20 Histology cases in 10 pairs of H&E slides in 20’ slots over 3 hours and 20’ on the second morning
♦ 4 macro cases are provided in the form of macro photographs of surgical specimens with clinical details.Two 20’ slots(2 cases each) + 20’ discussion with 2 examiners
♦ OSPEs:2x20’ examinations, one face to face with 2 examiners, the other written
♦ Long cases: 4 x 20’ (include histochemistry, immunohistochemistry, immunofluorescence and electron microscopy)
♦ Frozen sections: 6 cases in 2 x 20’ stations (3 each station)
♦Round table on how to restructure cytopathology training and exam at a Cytopathology Day which will take place on September 26, 2018 at Imperial College London