Current Concepts in Pathology CoCoPath Bulletin vol 1, issue 2 March/April 2015 ULTRASOUND-GUIDED FINE NEEDLE ASPIRATION BIOPSY: A KEY TOOL FOR THYROID NODULE EVALUATION The prevalence of thyroid nodules in North America ranges from 4-7% in the adult population, with an annual incidence of 0.1% (300,000 newly diagnosed nodules per year). By age 60, about 50% of all people have a thyroid nodule detected by either physical examination or imaging. The majority of thyroid nodules (>90%) are benign and do not cause symptoms. Typically nodules are detected incidentally by the patient, during routine physical examination, on radiographic imaging for unrelated reasons, or from abnormal thyroid function tests. Most thyroid nodules are non-functioning, and tests for thyroid hormones are typically normal. HISTORY AND PHYSICAL EXAMINATION Once a nodule is discovered, a complete history and physical examination is generally undertaken. Pertinent history includes a history of childhood head and neck irradiation, family history of thyroid carcinoma, or thyroid cancer syndrome (e.g., Cowden’s syndrome, familial polyposis, Carney complex, multiple endocrine neoplasia [MEN] 2, or Werner syndrome). Physical findings that could suggest malignancy include solitary nodule, hardness, fixation of nodule to surrounding tissues, vocal cord paralysis, and lateral cervical lymphadenopathy. Initial laboratory tests may include measurement of thyroid hormone (thyroxine or T4) and thyroid-stimulating test (TSH). Unfortunately, it is usually not possible to determine the malignant potential of a thyroid nodule by history, physical examination and blood tests alone. Further evaluation typically requires specialized testing by ultrasonography and fine needle aspiration (FNA) biopsy. FNA has also largely replaced nuclear thyroid scans as a first-line method of evaluation. Current Concepts in Pathology is a newsletter designed to keep our clinical colleagues updated on current topics in the field of pathology, and how they correlate with clinical practice. In this edition, Dr. Risha Ramdall, one of our cytopathologists, discusses the importance of ultrasound-guided FNA in the evaluation of thyroid nodules. Also presented is an abstract on a novel minimally invasive sampling technique with TFF3 immunohistochemistry in the evaluation of patients with potential Barrett’s esophagus. CoCoPath: Nader Shihabi M.D. Nick Byrne, M.D. Christine Cesca, M.D. Jeffrey Curtis, M.D. Dennis Hwang, M.D. Barry Latner, M.D. Rajni Mandal, M.D, Risha Ramdall, M.D. CONTRA COSTA PATHOLOGY ASSOCIATES 399 Taylor Blvd, Ste 200, Pleasant Hill, CA 94523 | Office: 925-270-3575 | Fax: 925-270-3589 | www.cocopath.net Continued from page 1 (Nuclear scans may still be useful in the setting of hyperthyroidism, as hyperfunctioning nodules rarely harbor malignancy and generally do not require FNA.) FINE NEEDLE ASPIRATION BIOPSY FNA is the most accurate and cost-effective method for evaluating thyroid nodules. No serious adverse side effects or seeding of tumor cells in the needle track have been reported. When performed by an experienced physician, specificity, sensitivity and predictive value are > 90%. When combined with ultrasound imaging and guidance, studies report lower rates of non-diagnostic and false-negative cytology results. Ultrasound-guided FNA is preferred for cystic nodules with a higher likelihood of non-diagnostic cytology (>25-50% cystic component) and nodules with a risk of sampling error (difficult to palpate or posteriorly located). Ultrasound imaging during FNA not only guides accurate needle placement directly into a nodule for optimal sampling, but provides information about nodule characteristics (i.e. solid, cystic, or complex) and its precise size and location. After initial examination, the ultrasound can also be used to follow patients with benign nodules to detect growth or shrinkage over time. Generally, thyroid nodules greater than 1 cm are biopsied due to higher risk of malignancy. In the presence of 2 or more thyroid nodules, ultrasound characteristics are used to determine which nodule is aspirated. When none of the nodules have a suspicious ultrasound appearance, only the largest nodule is biopsied, with observation and serial ultrasound examinations of the other nodules. FNA REPORTING The biopsy report will usually indicate a diagnosis falling under one of six categories set forth in the most recent classification by the 2007 National Cancer Institute Thyroid Fine Needle Aspiration State of the Science Conference. This expanded classification standardizes terminology for thyroid FNA cytology reporting: 1. Nondiagnostic/ Inadequate (< 5% of FNA biopsies; 1-4% risk of malignancy). A repeat aspiration biopsy with US-guidance is typically recommended. 2. Benign (60-70% of FNA biopsies; 0-3% risk of malignancy). Routine clinical follow-up at 6-18 month intervals is recommended. 3. Follicular Lesion of Undetermined Significance (3-6% of all thyroid FNA biopsies; 15% risk of malignancy). Recommended management requires clinical correlation. 4. Follicular Neoplasm/Suspicious for Neoplasm (15-30% risk of malignancy.) Surgical lobectomy is typically recommended. 5. Suspicious for Malignancy (60-75% risk of malignancy.) Surgical lobectomy or total thyroidectomy is recommended. 6. Malignant (3-7% of all thyroid FNAs; 97-99% risk of malignancy.) Total thyroidectomy is recommended. CONTRA COSTA PATHOLOGY ASSOCIATES 399 Taylor Blvd, Ste 200, Pleasant Hill, CA 94523 | Office: 925-270-3575 | Fax: 925-270-3589 | www.cocopath.net MOLECULAR DIAGNOSTICS Over the past decade, several molecular markers have emerged as possible diagnostic tools for providing a more definitive diagnosis for thyroid nodules with an indeterminate diagnosis on FNA biopsy. Somatic mutation testing (BRAF, RAS, RET/PTC and PAX8/PPAR-γ), gene expression profile analysis, immunocytochemistry (ICC) and miRNA analysis have all been tested in indeterminate thyroid lesions with reasonable success. However, every one of these markers has its own set of limitations, and none has yet been proven to perfectly distinguish benign from malignant nodules in FNA indeterminate cases. Furthermore, the gold standard to which these molecular tests are often measured up against – cytologic diagnosis – is imperfect, with discordances in up to 14% of cases, even after independent expert thyroid cytopathologist review. This potential for interobserver variability remains a weakness in any platform that relies on FNA diagnosis as its standard. remains the gold standard for the evaluation of a thyroid nodule. It is safe, accurate, and cost-effective, with a diagnostic accuracy of over 90%. Clinical management should be guided by the results of the ultrasound-guided FNA. The American Thyroid Association Guidelines Task Force is currently reviewing several commercially available gene expression markers in order to generate expert consensus guidelines on when and how to use these platforms. Given the clear limitations described, more progress in this technology is anticipated in the next few years. References: SUMMARY Compared to other diagnostic modalities at this point in time, FNA 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) Am J Clin Pathol 2009;132:658-665. Thyroid 2009; Vol 19, Number 11:1167-1214. J Clin Endocrinol Metab 81:3563–3569. Thyroid 1998; 8:15–21. Thyroid 1998;8:283–289. Diagn Cytopathol 36:425–437. J Clin Endocrinol Metab 87:1941–1946 J Clin Endocrinol Metab 91:3411–3417. J Clin Endocrinol Metab 87:4924–4927. N. Engl. J. Med. 367(8), 705–715 (2012). Expert Rev Mol Diagn. 2013;13(6):613-623. April is Head & Neck Cancer and Esophageal Cancer Awareness Month Evaluation of a minimally invasive cell sampling device coupled with assessment of trefoil factor 3 expression for diagnosing Barrett's esophagus: a multi-center case-control study. Ross-Innes CS et al; BEST2 Study Group. (71 collaborators) PLoS Med. 2015 Jan 29;12(1):e1001780. doi: 10.1371/journal.pmed.1001780. eCollection 2015. Abstract BACKGROUND: Barrett's esophagus (BE) is a commonly undiagnosed condition that predisposes to esophageal adenocarcinoma. Routine endoscopic screening for BE is not recommended because of the burden this would impose on the health care system. The objective of this study was to determine whether a novel approach using a minimally invasive cell sampling device, the Cytosponge, coupled with immunohistochemical staining for the biomarker Trefoil Factor 3 (TFF3), could be used to identify patients who warrant endoscopy to diagnose BE. METHODS AND FINDINGS: A case-control study was performed across 11 UK hospitals between July 2011 and December 2013. In total, 1,110 individuals comprising 463 controls with dyspepsia and reflux symptoms and 647 BE cases swallowed a Cytosponge prior to endoscopy. The primary outcome measures were to evaluate the safety, acceptability, and accuracy of the Cytosponge-TFF3 test compared with endoscopy and biopsy. In all, 1,042 (93.9%) patients successfully swallowed the Cytosponge, and no serious adverse events were attributed to the device. The Cytosponge was rated favorably, using a visual analogue scale, compared with endoscopy (p < 0.001), and patients who were not sedated for endoscopy were more likely to rate the Cytosponge higher than endoscopy (Mann-Whitney test, p < 0.001). The overall sensitivity of the test was 79.9% (95% CI 76.4%-83.0%), increasing to 87.2% (95% CI 83.0%-90.6%) for patients with 3 cm of circumferential BE, known to confer a higher cancer risk. The sensitivity increased to 89.7% (95% CI 82.3%-94.8%) in 107 patients who swallowed the device twice during the study course. There was no loss of sensitivity in patients with dysplasia. The specificity for diagnosing BE was 92.4% (95% CI 89.5%-94.7%). The case-control design of the study means that the results are not generalizable to a primary care population. Another limitation is that the acceptability data were limited to a single measure. CONCLUSIONS: The Cytosponge-TFF3 test is safe and acceptable, and has accuracy comparable to other screening tests. This test may be a simple and inexpensive approach to identify patients with reflux symptoms who warrant endoscopy to diagnose BE. CONTRA COSTA PATHOLOGY ASSOCIATES 399 Taylor Blvd, Ste 200, Pleasant Hill, CA 94523 | Office: 925-270-3575 | Fax: 925-270-3589 | www.cocopath.net 399 Taylor Blvd, Suite 200 Pleasant Hill, CA 94523 www.cocopath.net March/April 2015 CoCoPath Bulletin
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