Thyroid Cancer 05/07/2018. Maastricht Pathology 2018 June Maastricht The Netherlands. Thyroid Cytology in the MDT setting

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1 Maastricht Pathology 2018 June 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 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. 1

2 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) 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 CLINICAL PATHWAY PRIMARY CARE:URGENT REFERRAL Symptomatic patient GP GPs 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 lump Thyroid lump in patient >65 or<18 years of age Previous neck irradiation Associated cervical lymphadenopathy Voice change / hoarseness Family history thyroid cancer Thyroid Swelling AND Stridor The Thy classification adopted by the Royal College of Physicians ( 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). 2

3 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. 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 Diagnostic pitfalls Adequacy of material (skills of the aspirator, cellularity of the lesion and target) Overlapping morphologic features 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!) 3

4 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) 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 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 Jul;27(1):1-4 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 Jan-Feb;46(1):

5 Baskin HJ. Ultrasound-guided fine-needle aspiration biopsy of thyroid nodules and multinodular goiters. Endocr Pract May-Jun;10(3): 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 followup for nondiagnostic cytology is prudent 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. 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). Thy 3f (follicular neoplasm) Hypercellular Microfollicular arrangement Scanty colloid Regular nuclear outlines Fine chromatin Fragile cytoplasm No nuclear pseudoinclusions 5

6 Thy3 a and Thy3f subcategories H.R 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. 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. 6

7 The Thy classification adopted by the Royal College of Physicians Highly cellular aspirate containing numerous clusters and sheets of follicular cells showing nuclear crowding; Nuclear grooving and pseudoinclusions are occasionally identified 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. The epithelial fragments are seen within a background of moderate fluid colloid and mixed inflammatory cells. Therefore this is a Thy 4 What are the proportions of patients in each Thy classification? 7

8 The distribution of Thy categories in 2014 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 Total=2157 Thy5, 5% St Mary's Histology 118 Thy4, 3% Thy5, 4% Thy1, 9% Thy4, 3% Thy1, 14% Thy3, 9% Thy3 13% Thy2, 65% Thy2, 75% HH All Thy3-5 cases were discussed at the Central MDT Meeting, although the two labs (HH and SMH) were still independently reporting. The guidelines followed were the same. Thy4, Thy5, Thy1, Thy3, 4% 4% 6% 6% Thy2, 80% Which are the factors that may influence cyto-histo correlations? The operator The cytopathologist The MDT HH Results Malignanc y Benign Thy % Thy % Thy % SMH Thy % Thy % Thy % HH+SM H Thy % Thy % Thy % PPV = M/(M+B) 8

9 Conclusions In 2008 the proportion of Thy 3 cases, after almost 2 years of joint MDTs,changed (SM 13% vs 14%, HH 8%vs 5%) while PPV is more divergent. This is associated with a significant difference in the proportion of Thy3 cases receiving surgery in the two groups (HH=59%,SM=36%). MDT discussion of Thy3 cases influences significantly the management and outcome of such patients. How many patients have cytohisto correlation? 125 Total 308 cases SMH HH TOTAL cyto-histological correlations (340 cases) What is the positive predictive value of Thy3-5 categories? Chart Title THY1 THY2 THY3 THY4 THY5 9

10 Distribution of cases CHART TITLE THY1 THY2 THY3 THY4 THY5 16% 20% 6% Proportion of malignancy THY5 100% THY4 100% THY % THY2 13.3% 31% 27% Correlated cases Review of false negatives (12 cases-11 patients) 10

11 Conclusions 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 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 and better inform the management of the disease. Progress in Identifying Driver Mutations in Thyroid Cancer 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 Ref Nikiforov et al

12 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 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. Advantages, disadvantages and cost analysis of Sanger sequencing, pyrosequencing and Next Generation Sequencing in our lab From Darkness into Light Sequencing method Advantages Disadvantages Cost analysis Sanger -Relatively low cost/sample -Very stable technology -Relatively low sensitivity -Non quantitative -EC: 50, , PT: 10-12hrs No molecular marker One molecular marker Many molecular markers -CPS: 25 3 Pyro -Relatively low cost/sample -Detects single type of mutation -EC: 85,000 -Quantitative -Sensitive to background noise -PT: 8-10hrs -Sensitive -Foreknowledge of mutation -CPS: Quick (single working day) NGS -Small amount of DNA required -High cost/sample -EC: 80,000 -Quantitative -Takes up to three days -PT: 3 days -Very sensitive -Requires sufficient knowledge of bioinformatics -CPS: 200 -Simultaneous analysis of multiple cancer -Requires a lot of hands-on time hotspots -Requires specialist training 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 12

13 The Thyroid Nodule Congenital anomalies Thyroglossal duct cyst Inflammatory Lesions Inflammatory foci Compensatory regenerative nodules (?TSH,?TGI) Hyperplasia Neoplasia Benign Malignant Review of discordant cases Criteria Architecture (monolayers, crowded clusters) Cellularity (scanty,moderate,marked) Colloid (scanty-abundant,fluid-dense) Pseudoinclusions (absent,rare,abundant) Nuclear groovings (absent,rare,abundant) Chromatin pattern Nuclear membrane (smooth,irregular) Cytoplasm (amount, staining pattern) Naked nuclei (present, absent) Lymphocytes What to look for Type of cells (thyrocytes,macrophages, lymphocytes etc) Amount and type of colloid vs cellularity Bare nuclei Architecture Follicular lesions The morphological distinction of hyperplastic adenomatous nodules, welldifferentiated 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. 13

14 Granulomatous Thyroiditis (De Quervain-Subacute) Follicular cells with degenerative features (paravacuolar granules) Lymphocytes and polymorphs(subacute) Epithelioid and giant cells (granulomatous) Lymphocytic Thyroiditis (Hashimoto) Polymorphic lymphocytes (isolated and intraepithelial) Plasmacells Hurtle cell metaplasia Degenerative changes in follicular cells 14

15 Lymphocytic Thyroiditis (Hashimoto) Goitre Abundant fluid colloid Bland thyrocytes in follicles or sheets macrophages 15

16 Classification of Thyroid Neoplasms Epithelioid aggregates can look very worrying! Put in context Previous FNA??Background of goitre Primary follicular epithelial neoplasms Benign Follicular adenoma Malignant Differentiated: Papillary, Follicular Poorly Differentiated (Insular) Anaplastic Primary parafollicular epithelial neoplasms Medullary carcinoma?mixed/composite follicular cell-c cell Other primary epithelial neoplasms Primary non-epithelial neoplasms Secondary tumors Follicular lesion,cytologically benign Less fluid colloid Predominance of bland thyrocytes, usually arranged in microfollicles Few macrophages Naked nuclei Signs of hyper or hypofunctionality 16

17 Cellular Thy 2 Abundant fluid colloid Bare nuclei Groups of follicular cells Stromal fragments 3D rounded follicles 17

18 Adenomas Follicular neoplasm Hot Follicular carcinoma Hurtle Insular carcinoma Follicular lesion,cytologically suspicious Scanty or absent colloid Abundance of homogeneous or mildly atypical thyrocytes, usually arranged in microfollicles Absent macrophages Few or absent naked nuclei Criteria for Diagnosis of Follicular Carcinoma As per criteria of follicular adenoma and Capsular or vascular invasion 18

19 Solitary nodule in left lobe of a 48 y.o woman Solitary nodule in left lobe woman 48 y.o. Minimally invasive follicular carcinoma Thy 3 (follicular neoplasm) Hypercellular Microfollicular arrangement Scanty colloid Regular nuclear outlines Fine chromatin Fragile cytoplasm No nuclear pseudoinclusions Incidental micropapillary microcarcinoma 19

20 Cytology Follicular carcinoma Incidental papillary microcarcinoma Nuclear crowding Abundant dense cytoplasm Discohesive cells with preserved cytoplasm Solitary cold nodule Cellular smear Devoid of colloid Clusters and follicular groups Nucleoli Fine cytoplasmic granulations, occasionally with a polar pattern 20

21 Hurtle cells Suspicious Thy 5 or Thy 4? DD medullary Oncocytic variant of papillary Hurthle cell tumour BUT calcitonin negative Hurtle cell tumours Cytologically suspicious by definition Abundant orangiophilic cytoplasm (granular) Vesicular nucleus, prominent nucleolus R lobe solid nodule in MNG FNA of the L lobe showed Thy 2 Images are from the R lobe nodule 21

22 Nuclear crowding Irregular nuclear outlines Occasional pseudoinclusions 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 Hyalinising trabecular adenoma (Thy 4) Palisading, elongated cells arranged perpendicularly to metachromatic material Papillary Carcinoma 22

23 Cytologic Features of Papillary Carcinoma Crowded overlapping nuclei Irregular nuclear membrane Nuclear grooves Pale vacuolated nucleoplasm Peripheral margination of chromatin Nuclear pseudoinclusions Thy 5, papillary carcinoma 23

24 Pitfalls Medullary Carcinoma Pseudoinclusions can be mimicked by red blood cells overlying nuclei or by air bubbles ( which however normally involve both cytoplasm and nucleus) Plasmacytoid and /or spindle cells Cytoplasm granularity Usually dispersed but also trabecular or follicular pattern positive with calcitonin Pitfalls in thyroid tumour pathology J Rosai, E Kuhn, ML Carcangiu Histopathology 2006 (Aug)49:

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26 Nuclei in LBC and conventional smears Colloid in LBC and conventional smears Nuclear Pseudoinclusons and membrane irregularity 26

27 Papillary carcinoma in LBC Nuclear pseudoinclusions and membrane irregularity are equally identifiable in LBC albeit hyperchromatism is usually more prominent 27

28 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) The End! Any Questions? OSPEs Objective structured practical examination (OSPE) 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 28