The Use of Fine-Needle Aspiration (FNA) Cytology in Patients with Thyroid Nodules in Asia: A Brief Overview of Studies from the Working Group of Asian Thyroid FNA Cytology

Ultrasound-guided fine-needle aspiration (FNA) cytology is the most widely used screening and diagnostic method for thyroid nodules. Although Western guidelines for managing thyroid nodules and the Bethesda System for Reporting Thyroid Cytopathology are widely available throughout Asia, the clinical practices in Asia vary from those of Western countries. Accordingly, the Working Group of Asian Thyroid FNA Cytology encouraged group members to publish their works jointly with the same topic. The articles in this special issue focused on the history of thyroid FNA, FNA performers and interpreters, training programs of cytopathologists and cytotechnicians, staining methods, the reporting system of thyroid FNA, quality assurance programs, ancillary testing, and literature review of their own country’s products. Herein, we provide a brief overview of thyroid FNA practices in China, India, Japan, Korea, the Philippines, Taiwan, and Thailand.

Thyroid Fine-Needle Aspiration Cytology Practice in Korea

We reviewed the current status of thyroid fine-needle aspiration cytology (FNAC) in Korea. Thyroid aspiration biopsy was first introduced in Korea in 1977. Currently, radiologists aspirate the thyroid nodule under the guidance of ultrasonography, and cytologic interpretation is only legally approved when a cytopathologist makes the diagnosis. In 2008, eight thyroid-related societies came together to form the Korean Thyroid Association. The Korean Society for Cytopathology and the endocrine pathology study group of the Korean Society for Pathologists have been updating the cytologic diagnostic guidelines. The Bethesda System for Reporting Thyroid Cytopathology was first introduced in 2009, and has been used by up to 94% of institutions by 2016. The average diagnosis rates are as follows for each category: I (12.4%), II (57.9%), III (10.4%), IV (2.9%), V (3.7%), and VI (12.7%). The malignancy rates in surgical cases are as follows for each category: I (28.7%), II (27.8%), III (50.6%), IV (52.3%), V (90.7%), and VI (100.0%). Liquid-based cytology has been used since 2010, and it was utilized by 68% of institutions in 2016. The categorization of thyroid lesions into “atypia of undetermined significance” or “follicular lesion of undetermined significance” is necessary to draw consensus in our society. Immunocytochemistry for galectin-3 and BRAF is used. Additionally, a molecular test for BRAF in thyroid FNACs is actively used. Core biopsies were performed in only 44% of institutions. Even the institutions that perform core biopsies only perform them for less than 3% of all FNACs. However, only 5% of institutions performed core biopsies up to three times more than FNAC.

Current Practices of Thyroid Fine-Needle Aspiration in Asia: A Missing Voice

No abstract available.

The Intraoperative Immunohistochemical Staining of CD56 and CK19 Improves Surgical Decision for Thyroid Follicular Lesions

BACKGROUND: When differential diagnosis is difficult in thyroid follicular lesions with overlapping histological features, the immunohistochemical staining can help confirm the diagnosis. We aimed to evaluate the effectiveness of rapid immunohistochemical stains of CD56 and cytokeratin 19 on frozen sections of thyroid follicular lesion and explore the possible gains and limitations of the practice. METHODS: Eighty-six nodules of 79 patients whose intraoperative frozen sections were selected as the control group, and 53 nodules of 48 patients whose intraoperative frozen sections were subject to rapid immunohistochemistry were selected as the study group. RESULTS: Five nodules (6%) in the control group were diagnosed as follicular neoplasm and six nodules (7%) were deferred. In the study group, six nodules (11%) were follicular neoplasm and none were deferred. Three nodules (4%) in the control group showed diagnostic discrepancy between the frozen and permanent diagnoses, but none in the study group. The average turnaround time for the frozen diagnosis of the control group was 24 minutes, whereas it was 54 minutes for the study group. CONCLUSIONS: Intraoperative rapid immunohistochemical stains significantly decreased the diagnostic discrepancy in this study. Considering the adverse effects of indefinite frozen diagnosis or discrepancy with permanent diagnoses, the intraoperative rapid immunohistochemical stain can help to accurately diagnose and hence provide guidance to surgical treatment.

History of the Official Journal Published by the Korean Society of Pathologists: From the Korean Journal of Pathology to the Journal of Pathology and Translational Medicine

No abstract available.

Extremely Well-Differentiated Papillary Thyroid Carcinoma Resembling Adenomatous Hyperplasia Can Metastasize to the Skull: A Case Report

We describe herein histologic, immunohistochemical, and molecular findings and clinical manifestations of a rare case of an extremely well differentiated papillary thyroid carcinoma (EWD-PTC). Similarly, it is also difficult to diagnose follicular variant papillary thyroid carcinoma (FVPTC), whose diagnosis is still met with controversy. A recently reported entity of well-differentiated tumor of uncertain malignant potential (WDT-UMP) is added to the diagnostic spectrum harboring EWD-PTC and FVPTC. We report this case, because EWD-PTC is different from FVPTC in its papillary architecture, and also from WDT-UMP in its recurrence and metastatic pattern. These morphologically deceptive entities harbored diagnostic difficulties in the past because the diagnosis depended solely on histology. However, they are now diagnosed with more certainty by virtue of immunohistochemical and molecular studies. We experienced a case of EWD-PTC, which had been diagnosed as adenomatous hyperplasia 20 years ago and manifested recurrence with lymph node (LN) metastasis 7 years later. After another 7 years of follow-up, a new thyroid lesion had developed, diagnosed as FVPTC, with LN metastasis of EWD-PTC. One year later, the patient developed metastatic FVPTC in the skull. Immunohistochemically, the EWD-PTC was focally positive for CK19, negative for galectin-3, and focally negative for CD56. Molecular studies revealed BRAF-positivity and K-RAS negativity. The FVPTC in the left thyroid showed both BRAF and K-RAS negativity. In conclusion, EWD-PTC and FVPTC share similar histologic features, but they are different tumors with different molecular biologic and clinical manifestations. A large cohort of EWD-PTC should be included in further study.

Current Issues and Clinical Evidence in Tumor-Infiltrating Lymphocytes in Breast Cancer

With the advance in personalized therapeutic strategies in patients with breast cancer, there is an increasing need for biomarker-guided therapy. Although the immunogenicity of breast cancer has not been strongly considered in research or practice, tumor-infiltrating lymphocytes (TILs) are emerging as biomarkers mediating tumor response to treatments. Earlier studies have provided evidence that the level of TILs has prognostic value and the potential for predictive value, particularly in triple-negative and human epidermal growth factor receptor 2-positive breast cancer. Moreover, the level of TILs has been associated with treatment outcome in patients undergoing neoadjuvant chemotherapy. To date, no standardized methodology for measuring TILs has been established. In this article, we review current issues and clinical evidence for the use of TILs in breast cancer.

Anaplastic Transformation of Papillary Thyroid Carcinoma in a Young Man: A Case Study with Immunohistochemical and BRAF Analysis

This study reports a case of anaplastic transformation from a well-differentiated thyroid carcinoma in a young patient. The first recurrent tissue contained poorly differentiated foci that revealed lower thyroglobulin, thyroid transcription factor 1 (TTF-1), and galectin-3 expression than the well-differentiated area. However there was no increased p53 or Ki-67 expression in the poorly differentiated foci, nor in the well-differentiated area. The tissue subsequently relapsed and revealed only anaplastic features, complete loss of thyroglobulin, TTF-1, and galectin-3 expression and revealed an increase in p53 and Ki-67 expression. The BRAF V600E and BRAF V600V mutation were found in the initially diagnosed papillary thyroid carcinoma and the poorly differentiated foci of the recurring papillary thyroid carcinoma; however, only the BRAF V600V mutation was found in the anaplastic carcinoma. These results suggest that overexpression of p53 and Ki-67 contributed to the anaplastic transformation. We also found that the BRAF type changed during the tumor relapse.

Incidence and Malignancy Rates of Diagnoses in the Bethesda System for Reporting Thyroid Aspiration Cytology: An Institutional Experience

BACKGROUND: The Bethesda System for Reporting Thyroid Cytopathology (BSRTC) uses six diagnostic categories to standardize communication of thyroid fine-needle aspiration (FNA) interpretations between clinicians and cytopathologists. Since several studies have questioned the diagnostic accuracy of this system, we examined its accuracy in our hospital. METHODS: We calculated the incidences and malignancy rates of each diagnostic category in the BSRTC for 1,730 FNAs that were interpreted by four cytopathologists in Gangnam Severance Hospital between October 1, 2011, and December 31, 2011. RESULTS: The diagnostic incidences of categories I-VI were as follows: 13.3%, 40.6%, 9.1%, 0.4%, 19.3%, and 17.3%, respectively. Similarly, the malignancy rates of these categories were as follows: 35.3%, 5.6%, 69.0%, 50.0%, 98.7%, and 98.9%, respectively. In categories II, V, and VI, there were no statistically significant differences in the ranges of the malignancy rates among the four cytopathologists. However, there were significant differences in the ranges for categories I and III. CONCLUSIONS: Our findings suggest that institutions that use the BSRTC should regularly update their diagnostic criteria. We also propose that institutions issue an annual report of incidences and malignancy rates to help other clinicians improve the case management of patients with thyroid nodules.

The Definition of Minimal Extrathyroid Extension in Thyroid Pathology by Analyzing Sizable Intra- and Extrathyroid Blood Vessels

BACKGROUND: To define the exact boundary of the intrathyroid and extrathyroid aspects of a gland when determining the extent of cancer invasion, we plan to clarify the definition of sizable vascular structures, which is one of the helpful histologic clues in determining a minimal extrathyroid extension. We hypothesized that arterial wall thicknesses in extrathyroid soft tissue would be significantly different from the arteries in the thyroid parenchyma. METHODS: Twenty cases of papillary carcinoma were selected. The numbers and wall thicknesses of the arteries and arterioles in intrathyroid and extrathyroid tissue were evaluated. The absence of nerve tissue in the thyroid gland was confirmed using the S-100 protein immunohistochemical stain. RESULTS: The comparison of the mean thicknesses of the total arteries between the extrathyroid and intrathyroid tissues in the retrospective study (26.88 micrometer vs. 15.07 micrometer, respectively) and the prospective study (35.24 micrometer vs. 16.52 micrometer, respectively) revealed significant differences (p=0.000). The greatest thickness of the intrathyroid arteries was 67.93 micrometer. CONCLUSIONS: According to our results, the study showed that the extrathyroidal arteries were significantly thicker than the intrathyroidal arteries. We suggest that the sizable blood vessels of extrathyroidal arteries should be greater than 67.93 micrometer in thickness.

Primary Mucinous Cystadenocarcinoma of the Breast: Cytologic Finding and Expression of MUC5 Are Different from Mucinous Carcinoma

Mucinous cystadenocarcinoma (MCA) in the breast is a rare neoplasm. There have been 13 cases of primary breast MCA reported. The MCA presents as a large, partially cystic mass in postmenopausal woman with a good prognosis. The microscopic findings resemble those of ovarian, pancreatic, or appendiceal MCA. The aspiration findings showed mucin-containing cell clusters in the background of mucin and necrotic material. The cell clusters had intracytoplasmic mucin displacing atypical nuclei to the periphery. Histologically, the tumor revealed an abundant mucin pool with small floating clusters of mucin-containing tumor cells. There were also small cysts lined by a single layer of tall columnar mucinous cells, resembling those of the uterine endocervix. The cancer cells were positive for mucin (MUC) 5 and negative for MUC2 and MUC6. This mucin profile is different from ordinary mucinous carcinoma and may be a unique characteristic of breast MCA.

Galectin-3 Expression and BRAF Mutation in Cases of Cytologically Suspicious Papillary Thyroid Carcinoma

BACKGROUND: Fine needle aspiration, which is known as the most accurate and cost-effective method for diagnosis of thyroid nodule, still may result in indeterminate cases that are pauci-cellular and show minor nuclear atypia, but most cases are associated with suspicion of papillary thyroid carcinoma (PTC). A B-type Raf kinase (BRAF) mutation was found in about half of PTCs and galectin-3 was expressed by malignant tumors, helping us to differentiate malignancies from benign lesions. METHODS: Cases studied included histologically 44 confirmed PTC cases and 18 benign cases previously diagnosed as suspicious of PTC using cytologic examination. Cases were analyzed for galectin-3 expression by immunohistochemical staining and BRAF mutation by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with a new restriction enzyme. RESULTS: All 44 cases of PTC and 8 of 18 benign controls expressed galectin-3. BRAF mutations were found in only 9 of the 44 PTC cases. Assessment of galectin-3 expression demonstrated high sensitivity but low specificity. Evaluation of BRAF mutation revealed high specificity and low sensitivity. CONCLUSIONS: This study suggests that the combined application of these two methods for PTC of suspicious cytology is complementary.

Cytologic Features of Diffuse Sclerosing Variant of Papillary Carcinoma: Cytohistopathologic Analysis of 16 Cases

BACKGROUND: The exact preoperative diagnosis of diffuse sclerosing papillary carcinoma (DSPC) is required for aggressive surgical treatment due to its extended involvement with thyroid and neck lymph nodes. The present study investigated the cytomorphologic characteristics of DSPC and identified cytologic features for preoperative diagnosis of DSPC. METHODS: A retrospective review of cytologic and histologic features of 16 patients diagnosed with DSPC after thyroidectomy and underwent preoperative fine needle aspiration cytology (FNAC) was performed. RESULTS: Prominent psammoma bodies were observed in 16 (100%) and 10 (62.5%) cases of histology and FNAC, respectively. Lymphocytes were observed in nine (56.2%) and four (25.0%) cases, and squamous cells were noted in seven cases (43.7%) and one case (6.2%) on histology and FNAC, respectively. Nuclear grooves and inclusions, which are characteristics of papillary carcinoma, were observed in FNAC and histology slides in all 16 cases. CONCLUSIONS: DSPC displays prominent psammoma bodies and characteristic nuclear features of papillary carcinoma such as nuclear groove and inclusion in FNAC. However, the preoperative diagnosis of DSPC using only FNAC could be difficult due to the absence of other characteristic features such as lymphocytes and metaplastic squamous cells.

Fine Needle Aspiration Cytology of Subacute Granulomatous Thyroiditis: A Clinico-Cytological Review of 10 Cases with Immunocytochemical Analysis / 대한세포병리학회지

Although subacute granulomatous thyroiditis(SGT) is usually diagnosed clinically, papillary carcinoma or other thyroid conditions must be considered in the differential diagnosis. We retrospectively reviewed the clinical and fine-needle aspiration(FNA) cytologic findings seen in 10 SGT cases to decide what are the most reliable cytologic findings and the most helpful molecular tools for reaching a confident cytologic diagnosis. The most representative smear slides were retrieved to perform immunocytochemistry for cytokeratin19(CK19) and Ret protein. Five papillary carcinomas(PTCs) were included as controls. The constant and typical cytologic findings of SGT were multinucleated giant cells(MGCs) (100%), epithelioid granulomas(90%), an inflammatory dirty background(90%) and plump transformed follicular cells(80%) without fire-flare cells, oncocytic cells or transformed lymphocytes. The immunoreactivities for CK19(37.5%) and Ret(10%) of the follicular cells of SGT were less than those(CK19 and Ret:100%) of PTC. CK19 immunoreactivity of the MGCs was seen in only one case of PTC. There was no significant difference between CK19 and Ret immunocytochemical staining for the MGCs of both SGT and PTC. The results of this study demonstrate that the cytological diagnosis of SGT can be improved by employing a combination of the typical and constant diagnostic cytological features and immunocytochemical results.

Correlation and Accuracy Between Fine Needle Aspiration Cytology of Thyroid Lesions and Histopathologic Diagnosis: Analysis of 322 Histopathologically Confirmed Cases / 대한세포병리학회지

Fine needle aspiration (FNA) cytology is the decisive test in the preoperative diagnostics of thyroid nodules. Here we share our institutional experience about thyroid aspiration and give suggestions for suspicious cytology results. Three hundred twenty-two cases in 270 patients (mean age 47.4 years, 243 women and 27 men) who underwent thyroidectomy were reviewed. Among the 322 cases, the FNA diagnosis of "positive for malignancy" was 87 cases (27.0%), "suggestive of malignancy" 30 cases (9.3%), "suspicious for malignancy" 61 cases (18.9%), "negative for malignancy" 102 cases (31.7%), and "unsatisfactory smear" 42 cases (13.0%). Eighty seven cases (100%) out of "positive for malignancy", 29 cases (96.7%) out of "suggestive of malignancy", and 39 cases (64.0%) out of "suspicious for malignancy" were papillary carcinoma (148 cases, 95.5%), or follicular carcinoma (2 cases, 1.3%), or metastatic carcinoma (1 case, 0.6%). Seventeen patients who had only negative or unsatisfactory cytology underwent thyroidectomy and nine cases (52.9%) were papillary carcinoma. We suggest that: the cytology diagnosis of "suggestive of malignancy" could be regarded as "positive for malignancy", the cytology diagnosis of "suspicious of malignancy" should be carefully correlated with clinico-radiologic manifestation, and even a negative or unsatisfactory smear should be carefully followed up.

Macrofollicular Variant of Papillary Thyroid Carcinoma with Extensive Hemorrhage / 대한세포병리학회지

BACKGROUND: The macrofollicular variant of papillary thyroid carcinoma (MVPC) is characterized by macrofollicles occupying more than half of the tumor and demonstrating nuclear features of classic papillary carcinoma. It is difficult to recognize on fine needle aspiration (FNA) cytology due to the paucity of aspirated neoplastic cell clusters, especially when the tumor is associated with extensive areas of hemorrhage. CASE: A 34-year-old female presented with a well-demarcated nodule in the thyroid gland, diagnosed as a benign nodule on ultrasonography and computed tomography. FNA cytology smear revealed a few small aggregates of follicular cells with morphological features suspicious for papillary carcinoma, set in a background of hemorrhage, inflammatory cells, and hemosiderin-laden macrophages. Intraoperative frozen section revealed macrofollicular nests filled with hemorrhage and composed of follicular cells demonstrating nuclear clearing and grooves. CONCLUSION: MVPC is a rare but distinctive variant of papillary carcinoma, which is easily mistaken for adenomatous goiter or benign macrofollicular neoplasm on radiologic findings. The cytopathologist should alert oneself on encountering benign radiologic findings and any smear composed of scant numbers of follicular cells with nuclear features suspicious for papillary carcinoma despite the bland-looking background of hemorrhage and hemosiderin-laden macrophages, and recommend intraoperative frozen sections for a definite diagnosis.