Thyroid Fine-needle Aspiration Research Articles

Performance of thyroid fine needle aspiration biopsy in a low- and middle-income country.

Introduction The 6 categories of the Bethesda System for Reporting Thyroid Cytology (TBSRTC) with associated risk of malignancy (ROM) provide evidence-based clinical management guidelines. This study aimed to determine the ROM and accuracy of FNAB in South Africa (SA). Methods Thyroid specimens from 3 pathology laboratories registered between January 2015 and December 2019 were considered for inclusion. ROM was obtained per TBSRTC category by cytohistological correlation and dividing the total number of specimens with malignant histology by the total number of cases operated. Accuracy was calculated based on the Bethesda category and eventual malignant histology. Results Seventeen thousand seven hundred and seventy-three histology and 4 791 cytology cases were identified. Of the 4 791 cytology cases, 931 (19%) underwent surgery. More than a third (333, 35.8%) of cases were confirmed as malignant following histological assessment, with the majority being benign (584, 62.7%). The ROM for the non-diagnostic and benign categories was 24.3% and 20.5%. The highest ROM was for category VI (91.5%), followed by categories V (69.5%), IV (51.9%) and III (38.8%). Thyroid FNAB had a sensitivity of 73%, specificity of 74%, and overall accuracy of 74%. Conclusion Bethesda categories II and IV have a relatively higher ROM in SA compared to findings from other developed countries. The diagnostic accuracy of thyroid FNAB in SA and the high rate of non-diagnostic diagnoses (38%) require further investigation. A national thyroid registry could provide location-specific data to aid the implementation of appropriate local policies and national guidelines for practicing thyroid surgeons.

Study of Thyroid Function Tests in Patients with Metabolic Syndrome

Study of Thyroid Function Tests in Patients with Metabolic Syndrome

Atypia of Undetermined Significance in Thyroid Fine Needle Aspiration Cytology Revisited

Atypia of Undetermined Significance in Thyroid Fine Needle Aspiration Cytology Revisited

Revisiting the utility of identifying nuclear grooves as unique nuclear changes by an object detector model.

Among other structures, nuclear grooves are vastly found in papillary thyroid carcinoma (PTC). Considering that the application of artificial intelligence in thyroid cytology has potential for diagnostic routine, our goal was to develop a new supervised convolutional neural network capable of identifying nuclear grooves in Diff-Quik stained whole-slide images (WSI) obtained from thyroid fineneedle aspiration. We selected 22 Diff-Quik stained cytological slides with cytological diagnosis of PTC and concordant histological diagnosis. Each of the slides was scanned, forming a WSI. Images that contained the region of interest were obtained, followed by pre-formatting, annotation of the nuclear grooves and data augmentation techniques. The final dataset was divided into training and validation groups in a 7:3 ratio. This is the first artificial intelligence model based on object detection applied to nuclear structures in thyroid cytopathology. A total of 7,255 images were obtained from 22 WSI, totaling 7,242 annotated nuclear grooves. The best model was obtained after it was submitted 15 times with the train dataset (14th epoch), with 67% true positives, 49.8% for sensitivity and 43.1% for predictive positive value. Conclusion: The model was able to develop a structure predictor rule, indicating that the application of an artificial intelligence model based on object detection in the identification of nuclear grooves is feasible. Associated with a reduction in interobserver variability and in time per slide, this demonstrates that nuclear evaluation constitutes one of the possibilities for refining the diagnosis through computational models.

Diagnostic interobserver agreement for thyroid fine-needle aspirates: Effects of reviewer experience and molecular diagnostics.

Few cytologically indeterminate thyroid fine-needle aspirations (FNAs) harbor BRAF V600E. Here, we assess interobserver agreement for The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) category III (atypia of undetermined significance [AUS]) FNAs harboring BRAF V600E and contrast their features with those harboring non-BRAF V600E alterations, with attention to cytopathology experience. Seven reviewers evaluated 5 AUS thyroid FNAs harboring BRAF V600E. To blind reviewers, cases were intermixed with 19 FNAs falling within other TBSRTC categories and in which genetic alterations other than BRAF V600E had been identified (24 FNAs total). Interobserver agreement against both "index" and most popular ("mode") diagnoses was calculated. Four additional BRAF V600E cases were independently reviewed. Reviewers included 3 trainees and 3 American Board of Pathology (board)-certified cytopathologists. Board-certified cytopathologists, whose experience ranged from 2 to more than 15 subspecialty practice years, had known AUS rates. BRAF V600E was identified in 5 of 260 (2%) AUS FNAs. Interobserver agreement was higher among cytopathologists with more experience. Mode diagnosis differed from index diagnosis in 6 of 11 cases harboring RAS-like alterations; mode diagnosis was AUS in 4 of 5 BRAF V600E FNAs. Atypia of undetermined significance of thyroid FNAs harboring BRAF V600E is uncommon yet relatively reproducible, particularly among pathologists with experience. It is advisable to sequence BRAF across V600 in such cases.

A case series of thyroid fine needle aspiration biopsies diagnosed as follicular neoplasm with oncocytic features.

Oncocytic lesions of the thyroid are a heterogeneous group encompassing nonneoplastic and neoplastic entities ranging from benign to malignant and have traditionally been classified as separate entities in thyroid pathology. To illustrate the diversity of these thyroid lesions, we describe three cases of fine needle aspiration biopsies (FNAB) diagnosed as Bethesda Category IV: Follicular neoplasm, oncocytic type, under the 2017 Bethesda System for Reporting Thyroid Cytopathology (TBSRTC), with ThyroSeq v3 molecular testing and subsequent surgical excision.

Stepwise analysis of thyroid diagnostic modalities with genomic imprinting detection.

The current preoperative malignancy risk evaluation for thyroid nodules involves stepwise diagnostic modalities including ultrasonography, thyroid function serology and fine-needle aspiration (FNA) cytopathology, respectively. We aimed to substantiate the stepwise contributions of each diagnostic step and additionally investigate the diagnostic significance of quantitative chromogenic imprinted gene in-situ hybridization (QCIGISH)-an adjunctive molecular test based on epigenetic imprinting alterations. A total of 114 cytopathologically-diagnosed and histopathologically-confirmed thyroid nodules with complete ultrasonographic and serological examination records were evaluated using QCIGISH in the study. Logistic regression models for thyroid malignancy prediction were developed with the stepwise addition of each diagnostic modality and the contribution of each step evaluated in terms of discrimination performance and goodness-of-fit. From the baseline model using ultrasonography [area under the receiver operating characteristics curve (AUROC): 0.79; 95% confidence interval (CI): 0.71-0.86], significant improvements in thyroid malignancy discrimination were observed with the stepwise addition of thyroid function serology (AUROC: 0.82; 95% CI: 0.74-0.90; P=0.23) and FNA cytopathology (AUROC: 0.88; 95% CI: 0.81-0.94; P=0.02), respectively. The inclusion of QCIGISH as an adjunctive molecular test further advanced the preceding model's diagnostic performance (AUROC: 0.95; 95% CI: 0.91-1.00, P=0.007). Our study demonstrated the significant stepwise diagnostic contributions of standard clinical assessments in the malignancy risk stratification of thyroid nodules. However, the addition of molecular imprinting detection further enabled a more accurate and definitive preoperative evaluation especially for morphologically indeterminate thyroid nodules and cases with potentially discordant results among standard modalities.

Thyroid nodules with DICER1 mutation or PTEN alteration: A comparative cytologic, clinical, and molecular study of 117 FNA cases.

DICER1 mutations and PTEN alterations are increasingly detected by thyroid fine-needle aspiration (FNA). Both are associated with nodular thyroid disease and cancer. The authors analyzed a large comparative thyroid FNA cohort with DICER1 mutation or PTEN alteration. A total of 117 thyroid FNAs with DICER1 or PTEN alterations were retrieved from the databases of two academic medical institutions. Demographic, clinical, and radiologic data were collected; FNA slides were analyzed for 29 cytomorphologic features. Of 117 thyroid FNAs, 36 (30.8%) had DICER1 mutation and 81 (69.2%) showed PTEN alteration. The DICER1 cohort had 33 (91.7%) females and three (8.3%) males (mean, 40.9 years); 61.8% had multinodular disease. FNAs were classified as atypia of undetermined significance (AUS), 23 (63.9%); follicular neoplasm (FN), 12 (33.3%); and malignant, 1 (2.8%). The PTEN subgroup had 66 (81.5%) females and 15 (18.5%) males (mean, 55.2 years) with increased multinodular disease (93.8%, p=.0016). PTEN FNAs had greater cytologic diversity: non-diagnostic, 2 (2.5%); benign, 5 (6.2%); AUS, 44 (54.3%); FN, 24 (29.6%); and malignant, 6 (7.4%). Both DICER1 and PTEN cases showed a range of resected tumor subtypes. The DICER1 cohort included thyroblastoma, and the PTEN group included anaplastic carcinoma. The cytomorphology of DICER1 and PTEN cases showed overlapping features, especially microfollicular patterns. Minor cytomorphologic differences included papillary patterns in DICER1 (p=.039), and oncocytic changes (p<.0001) in PTEN. DICER1 and PTEN FNAs reveal many cytologic similarities. DICER1 patients are younger, and PTEN patients had multinodular disease. Awareness of these genetic cohorts can identify patients at risk for thyroid cancer.

Comprehensive evaluation of cytomorphologic, histologic, and molecular features of DICER1-altered thyroid lesions on FNA: A multipractice experience.

DICER1 mutations, though infrequent, are encountered on preoperative molecular testing of indeterminate adult and pediatric thyroid fine-needle aspiration (FNA) specimens. Yet, published cytomorphologic features of DICER1-altered thyroid lesions are limited. Cytomorphological features of DICER1-altered thyroid lesions were examined in a multipractice FNA cohort with clinical, radiological, and histologic data. The cohort comprised 18 DICER1-altered thyroid FNAs, with 14 having slides available and eight having corresponding surgical resections. Smears, ThinPrep, and formalin-fixed cell block slides were reviewed and correlated with histology, when available. Clinical and radiologic data were obtained from the medical record. Most DICER1-altered FNAs were classified as atypia of undetermined significance (94.4%). DICER1 mutations occurred in codons 1709 (50%), 1810 (27.8%), and 1813 (22.2%). One patient had an additional DICER1 p.D1822N variant in both of their FNAs. Lesions were often hypoechoic (35.3%) and solid (47.1%) on ultrasound. Notable cytomorphologic features include mixed but prominent microfollicular or crowded component, variable colloid, and insignificant nuclear atypia. On resection (n=10), histologic diagnoses ranged from benign follicular adenoma and low-risk follicular thyroid carcinoma to high-grade follicular-derived nonanaplastic thyroid carcinoma. Subcapsular infarct-type change was the most common histologic change. There was no evidence of recurrence or metastasis in eight patients on limited follow-up. DICER1-altered thyroid lesions occurred frequently in young females and FNAs show RAS-like cytomorphology including crowded, mixed macro-/microfollicular pattern, and bland nuclear features. On resection, DICER1-altered thyroid lesions include benign (50%), low-risk lesions (30%), or high-risk malignancies (20%).

Current State of Molecular Cytology in Thyroid Nodules: Platforms and Their Diagnostic and Theranostic Utility.

The high prevalence of thyroid nodules and increased availability of neck ultrasound have led to an increased incidence of diagnostic thyroid fine needle aspirations, with approximately 20% yielding indeterminate results. The recent availability of molecular tests has helped guide the clinical management of these cases. This paper aims to review and compare three main commercially available molecular cytology platforms in the U.S.-Afirma GSC, Thyroseq GC, and ThyGeNEXT + ThyraMIR. Sequential improvements of the Afirma GSC and Thyroseq GC tests have increased positive and negative predictive values, sensitivity, and specificity. Comparative studies revealed similar diagnostic performance between these tests, with considerations for factors such as cost and processing time. Thyroseq GC provides detailed genomic information and specific management recommendations. ThyGeNEXT + ThyraMIR, though less studied, presents promising results, particularly in miRNA analysis for weak driver mutations. Challenges in interpreting results include variations in reporting and the evolving nature of testing platforms. Questions persist regarding cost-effectiveness and the utility of ultrasound characteristics in selecting candidates for molecular testing. While molecular testing has primarily served diagnostic purposes, advancements in understanding genetic alterations now offer therapeutic implications. FDA-approved options target specific genetic alterations, signaling a promising future for tailored treatments.

A Preliminary Study Comparing the Performance of Thyroid Molecular Tests to a Deep Learning Algorithm in Predicting Malignancy in Indeterminate Thyroid Fine Needle Aspiration Biopsies.

A Preliminary Study Comparing the Performance of Thyroid Molecular Tests to a Deep Learning Algorithm in Predicting Malignancy in Indeterminate Thyroid Fine Needle Aspiration Biopsies.

Effect of Music Therapy on Pain During Thyroid Fine Needle Aspiration Biopsy; A Randomized Controlled Clinical Trial

IntroductionHigh-resolution ultrasonography devices have led to the increased detection of thyroid nodules and the need for fine-needle aspiration biopsy (FNAB). However, FNAB is an invasive procedure that can cause discomfort and pain. Music therapy has been used for centuries to alleviate pain, and our clinical trial was conducted to investigate its impact on pain scores during thyroid FNAB. Materials and methodsWe conducted a randomized, controlled clinical trial, including adult patients undergoing thyroid FNAB. We evaluated the nonpharmacological intervention of listening to music before and during thyroid FNAB. We used a slow, nonlyrical, flowing melody with a tempo of 60 to 80 beats per minute as a therapeutic intervention for managing anxiety and pain. It had low tones, minimal percussion, and a volume of around 60 dB. The Beck Anxiety Inventory and Visual Pain Scale were used. ResultsThe study included 529 patients assigned to either the music group (n = 258, 48.7%) or the control group (n = 271, 51.2%). The patients were categorized into subgroups based on either a single nodule (73.63%) or multiple nodules (24.18%). When all patients or single nodule and multiple data are examined separately, the intervention group showed statistically significantly lower pain scores than the control group. ConclusionOur study is among the first on this topic and the largest in the available literature to demonstrate that listening to music during FNAB significantly reduces pain and anxiety. Music therapy is an effective, safe, and noninvasive intervention that can improve patient care and reduce distress and pain.

Does the Adoption of Molecular Testing Cause Decreased Thyroidectomy Rates in a National Cohort? A Quasiexperimental Study of High- Versus Low-Adoption States.

Background: Over the last decade, the utilization of molecular testing (MT) for the evaluation of thyroid nodules has increased. Rates and patterns of adoption of MT and its effect on thyroidectomy rates nationally are unknown. Varying rates of MT adoption at the state level provide an opportunity to study the effects of MT on thyroidectomy rates using a quasiexperimental study design. Methods: We performed a retrospective analysis of American adult patients in the Merative™ MarketScan® Research Databases who underwent thyroid fine-needle aspiration (FNA) from 2011 to 2021. MT included commercially available DNA and RNA platforms and traditional targeted mutational analysis. Interrupted time series analysis was used to evaluate the inflection of MT adoption and thyroidectomy rates after 2015. Difference-in-differences (DID) analysis was used to causally analyze the effect of MT adoption on thyroidectomy rates in high-adoption (at least a 10% increase in MT utilization) versus low-adoption states (no more than 5% increase in MT utilization) from 2015 to 2021. Results: We identified 471,364 patients who underwent thyroid FNA. The utilization of MT increased over the study period from 0.01% [confidence interval, CI: 0.00% to 0.02%] to 10.1% [CI: 9.7% to 10.5%], in 2021, with an immediate (β2 = 1.61, p = 0.002) and deeper (β3 = 0.6, p < 0.001) increase in MT adoption after 2015. Utilization of MT was lower in black patients, the elderly, rural areas, and patients with Medicaid (p < 0.05). Thyroidectomy rates were inversely correlated with MT utilization (r = -0.98, p < 0.0001). From 2015 to 2021, the average MT utilization rate increased from 2.4% to 15.3% in high-adoption states and 1.6% to 5.6% in low-adoption states. In low-adoption states, thyroidectomy rates decreased more but to similar levels (18.5-13.2%) compared with high-adoption states (15.9-13.4%) with an adjusted DID rate of -3.3% [CI -5.6% to -0.8%]. Conclusions: The acceleration in adoption of MT after 2015 likely coincides with the publication of American Thyroid Association guidelines. Black, elderly, and rural patients are less likely to receive MT. Although thyroidectomy rates were inversely correlated with MT utilization, our study suggests that this correlation is not causal. The effect of MT on thyroidectomy rates may be overshadowed by decreasing aggressiveness of thyroid nodule evaluation.

Postoperative recurrence of diffuse sclerosing thyroid cancer in an adolescent patient: A case report.

Papillary thyroid cancer is an inert malignant tumor with a good response to surgical treatment, low recurrence and metastasis rate, and good prognosis. Diffuse sclerosing thyroid cancer is an invasive subtype that is more common in young people, with a higher rate of lymph node metastasis and recurrence, and a relatively poor prognosis. A 13-year-old girl underwent radical surgery for diffuse sclerosing thyroid cancer. Eight years later, due to a large number of lymph node metastases, she underwent another radical surgery on her neck lymph nodes. The patient thyroid ultrasound and neck enhanced CT indicated that the patient had multiple enlarged lymph nodes in the neck with irregular morphology and structure, and the possibility of metastatic lymph nodes was high. Subsequently, the patient underwent thyroid fine-needle aspiration and the results showed that cancer cells were detected in both cervical lymph nodes. The patient was diagnosed with bilateral cervical lymph node metastases after thyroid surgery. After the second surgery, the patient recovered well, and no residual or focal iodine uptake tissue was found on the enhanced CT examination. As diffuse sclerosing thyroid cancer is prone to lymph node and recurrent metastases, once it is diagnosed, radical treatment should be actively performed. Postoperative adjuvant radiation therapy should be administered according to the patient condition and regular follow-ups should be conducted to monitor neck lymph node metastasis.

Comparison of Liquid-Based Preparations with Conventional Smears in Thyroid Fine-Needle Aspirates: A Systematic Review and Meta-Analysis.

To compare conventional smears (CSs) and liquid-based preparations (LBPs) for diagnosing thyroid malignant or suspicious lesions. Studies in the PubMed, SCOPUS, Embase, Web of Science, and Cochrane database published up to December 2023. We reviewed 17 studies, including 15,861 samples. The diagnostic odds ratio (DOR) for CS was 23.6674. The area under the summary receiver operating characteristic curve (AUC) was 0.879, with sensitivity, specificity, negative predictive value, and positive predictive value of 0.8266, 0.8668, 0.8969, and 0.7841, respectively. The rate of inadequate specimens was 0.1280. For LBP, the DOR was 25.3587, with an AUC of 0.865. The sensitivity, specificity, negative predictive value, and positive predictive value were 0.8190, 0.8833, 0.8515, and 0.8562. The rate of inadequate specimens was 0.1729. For CS plus LBP, the AUC was 0.813, with a lower DOR of 9.4557 compared to individual methods. Diagnostic accuracy did not significantly differ among CS, LBP, and CS plus LBP. Subgroup analysis was used to compare ThinPrep and SurePath. The DORs were 29.1494 and 19.7734. SurePath had a significantly higher AUC. There was no significant difference in diagnostic accuracy or proportion of inadequate smears between CS and LBP. SurePath demonstrated higher diagnostic accuracy than ThinPrep. Recommendations for fine-needle aspiration cytology should consider cost, feasibility, and accuracy.

A Comprehensive Approach to the Thyroid Bethesda Category III (AUS) in the Transition Zone Between 2nd Edition and 3rd Edition of The Bethesda System for Reporting Thyroid Cytopathology: Subcategorization, Nuclear Scoring, and More

Significant interobserver variabilities exist for Bethesda category III: atypia of undetermined significance (AUS) of The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). Thus, subcategorization of AUS including AUS “nuclear” and AUS “other” is proposed in the recent 3rd edition of TBSRTC. This study investigated the impact of the nuclear features/architectural features/nuclear score (NS) (3-tiered)/subcategories and subgroups on risk of malignancy (ROM) in thyroid fine-needle aspirations (FNA). 6940 FNAs were evaluated. 1224 (17.6%) cases diagnosed as AUS were reviewed, and 240 patients (initial FNAs of 260 nodules and 240 thyroidectomies) were included. Subcategories and subgroups were defined according to TBSRTC 2nd and 3rd editions. Histological diagnostic groups included nonneoplastic disease, benign neoplasm, low-risk neoplasm, and malignant neoplasm. Overall, ROM was 30.7%. ROM was significantly higher in FNAs with nuclear overlapping (35.5%), nuclear molding (56.9%), irregular contours (42.1%), nuclear grooves (74.1%), chromatin clearing (49.4%), and chromatin margination (57.7%), and these features were independent significant predictors for malignancy. FNAs with NS3 had significantly higher ROM (64.2%). Three-dimensional groups were significantly more frequent in malignant neoplasms (35.7%). ROM was significantly higher in AUS-nuclear subcategory (48.2%) and in AUS-nuclear and architectural subcategory (38.3%). The highest ROM was detected in AUS-nuclear1 subgroup (65.2%). ROM was significantly higher in the group including AUS-nuclear and AUS-nuclear and architectural subcategories, namely “high-risk group” than the group including other subcategories, namely “low-risk group” (42.0%vs 13.9%). In conclusion, subcategorization may not be the end point, and nuclear scoring and evaluation of architectural patterns according to strict criteria may provide data for remodeling of TBSRTC categories.

Diagnostic implication of thyroid spherules for cytological diagnosis of thyroid nodules.

Thyroid fine-needle aspiration (FNA) is a principal diagnostic procedure for thyroid nodules. A specific cytomorphological structure, known as the thyroid spherule, is often seen in FNA specimens. The clinical significance of these spherules in terms of diagnosis and prevalence remains largely unexplored. We performed a retrospective study on 310 thyroid FNA specimens and categorized them according to the Bethesda System for Reporting Thyroid Cytopathology. The presence, size and number of thyroid spherules in each specimen were examined and these data were subsequently correlated with the clinicopathological features. Thyroid spherules were almost exclusively detected in benign cases, comprising 7.6% of all benign diagnoses. The average diameter of spherules in benign cases was 84.9 μm. Benign cases and cases with atypia of undetermined significance cases primarily exhibited low cellularity, while follicular neoplasms and malignant cases typically showed moderate to high cellularity. In the subgroup of FNA cases with moderate to high cellularity, spherules were identified in 12 (20%) of 59 benign FNA cases. Within this group, the sensitivity and specificity of thyroid spherules for detecting benign FNA cases were 20% and 100%, respectively. Our results suggest that the presence of thyroid spherules in FNA specimens can serve as a highly specific marker for benign thyroid conditions. The prevalence of spherule detection is strongly influenced by the cellularity. In cases with moderate to high cellularity, the identification of spherules can assist the cytopathologists in diagnosing thyroid FNA cases as benign.

Cytomorphological comparison of ThinPrep and SurePath liquid-based cytology in thyroid fine-needle aspiration.

The two widely established systems for liquid-based cytology (LBC), ThinPrep and SurePath, employ different principles. The aim of this study was to compare the cytomorphology of thyroid lesions prepared by the two techniques. We retrospectively reviewed 44 thyroid FNA specimens prepared by LBC, including 20 ThinPrep and 22 SurePath. Cytologic diagnoses were made according to the Bethesda system and cytomorphologic parameters were evaluated. Acellular smears were significantly frequent in ThinPrep than SurePath (10% vs. 0%). Both techniques produced a clean background, well cell preservation, and not apparent cell shrinkage. ThinPrep showed significantly lower cellularity than SurePath (25% vs. 4.3%). ThinPrep produced considerable flattening and fragmented clusters, while SurePath contained larger clusters in a three-dimensional configuration. Colloid was significantly reduced in amount and fragmented in ThinPrep, and was easily observed in SurePath. In cases of Hashimoto's thyroiditis, ThinPrep produced much less leukocytes in background than SurePath. Aggregates of fibrin and leukocytes were frequently present in 10/16 cases (62.5%) processed by ThinPrep. Air-dry artifact at periphery of the ring was present in 6/16 cases (37.5%) processed by ThinPrep. The nuclear features of papillary carcinoma were similarly evident in both LBC preparations. SurePath seems to be superior to ThinPrep for diagnosing benign entities based on adequate representation of colloid and lymphocytes. The cell quality of both techniques in thyroid FNA was comparable, while each method introduces its own unique cytologic artifacts related to its methodology. We should recognize the cytomorphologic alterations to avoid misinterpretations.

P-82 Riedel's thyroiditis: three-year follow-up under steroid, rituximab and mycophenolate mofetil treatment

Abstract Introduction Riedel's thyroiditis (RT) is an uncommon thyroiditis characterized by fibrosis, macrophage, and eosinophil infiltration and is assumed to be the primary cause of autoimmunity in the pathogenesis. Invasion of the surrounding tissues, particularly the trachea, occurs. RT is also regarded as thyroid involvement in IgG4-related systemic illness. Because there is no conventional medical treatment protocol for RT, this paper aims to highlight the problems we had in diagnosing and our approach throughout therapy. Clinical Case In the last 1.5 years, a 44-year-old female patient on levothyroxine replacement diagnosed with hypothyroidism developed bilateral swelling in the eyes, double vision, drooping eyelids, shortness of breath, and feeling something lodged in the throat. A diffusely enlarged and stiff thyroid gland was palpated in her physical examination. Neck CT revealed a diffusely enlarged thyroid gland 7cm in diameter and constricted trachea. She did not have any constitutional symptoms. According to physical and radiologic exams, preliminary differential diagnoses were anaplastic thyroid carcinoma and IgG4-related thyroiditis. In laboratory tests, TSH: 4.5 mIU/L, st3-4: normal, Anti TPO: +++ TRAB: 0.15 U/L, ANA: Negative, IgG4: 0.52 g/L (0.03-2.01), ACE:21.39. Since the thyroid fine needle aspiration biopsy reported a hypocellular smear, a lacrimal gland biopsy was performed for systemic involvement of IgG4 related disorder's. Her dyspnea was becoming critical; therefore, she was administered 0.5 mg/kg steroid for two weeks before the scheduled bilateral total thyroidectomy, and a considerable decrease in dyspnea, swallowing sensations, and regression in compression findings were seen. Lacrimal biopsies demonstrated persistent inflammation with plasma cells and severe fibrosis, consistent with late-stage IgG4-related illness. Both thyroid lobes were enlarged in neck T1 and T2-weighted MRI images (right lobe was 34×25×68 mm, the left lobe was 35×26×69 mm), diffuse hypointensity was noted, contrast uptake decreased in the thyroid parenchyma following IVCM, and the data was determined to be compatible with RT. The thyroid gland grew markedly on PET-CT, narrowing the air column, with increased FDG absorption in a heterogeneous character (SUVmax: 4.9), and mild-moderate involvement in bilateral lacrimal and parotid glands.The decision was made to continue steroid treatment at 1 mg/kg for one month. Rituximab was given twice every six months while the steroid was lowered. Mycophenolate mofetil (MMF) (2×500 mg) was introduced as a maintenance immunosuppressive medication. The initial radiologic findings regressed in the control neck MRI and PET-CT in the first year. The MRI findings were also steady in the second and third years of MMF. Conclusion Immunosupression therapy with steroid, rituximab and MMF was effective in our RT patient for the long term without significant complications. Clinical and radiological responses similar to surgery can be obtained with immunosuppressive agents.Figure 1.PET-CT and MRI images at diagnosis and third year

Interpreting thyroid fine-needle aspiration biopsy

One of the most commonly seen abnormalities of the thyroid gland is the thyroid nodule. A thorough clinical evaluation of the nodule includes careful history taking and physical examination, laboratory tests, neck ultrasound (US), and fine-needle aspiration (FNA). Although thyroid FNA serves as an important test with an accurate result, when paired along with US, the results obtained are superior to that obtained only with an FNA. Thyroid FNA or biopsy is an accurate test for determining malignancy in a nodule and is an integral part of current thyroid nodule evaluation. Results are superior when FNA is performed with ultrasound guidance. FNA results are classified as diagnostic (satisfactory) or nondiagnostic (unsatisfactory). The hypocellular specimens produce unsatisfactory or nondiagnostic smears whereas satisfactory or diagnostic smears are categorized as benign, indeterminate, or malignant. In this article, we describe the indications and interpretation of thyroid fine-needle aspiration cytology. The Bethesda Cytologic Classification has a 6-category classification and has been described in the text.