Fine Needle Aspiration Cytology Research Articles

Combined modalities for the rapid diagnosis of patients with suspected tuberculous lymphadenitis: A cross-sectional study.

In settings with high burden of extrapulmonary tuberculosis, the use of various diagnostic modalities can result in superior and quick diagnosis leading to prompt initiation of treatment. This study assessed the diagnostic performance of the fine-needle aspiration cytology (FNAC), Ziehl-Neelsen (ZN) stain, fluorescence microscopy (FM) and cartridge-based nucleic acid amplification test (CBNAAT) in patients with suspected tuberculous lymphadenitis (TBLN). This cross-sectional studyodes, who underwent FNAC. The FNAC samples were subjected to cytomorphological examinati involved 255 patients clinically suspected of TBLN with palpable lymph non, ZN stain, FM and CBNAAT. The diagnostic performance of each modality was compared with CBNAAT, and combined performance was determined. The diagnostic performance of CBNAAT was determined by comparing it with composite reference standard. Of 255 patients, 148 (58.04%) showed features of TBLN on FNAC. The presence of epithelioid cell granulomas with caseous necrosis (67.57%) was the predominant cytomorphological pattern. On ZN stain, FM and CBNAAT, 31 (20.95%), 63 (42.57%) and 100 (67.57%) patients were found to be positive for TBLN, respectively. The sensitivity, specificity, positive predictive value and negative predictive value of CBNAAT was 58.59%, 91.83%, 92% and 58.06%, respectively. Finally, the combination of ZN stain, FM and CBNAAT led to the detection of 88.51% patients with TBLN. Combined use of ZN stain, FM and CBNAAT leads to superior and swift diagnosis of patients with clinically suspected TBLN.

The Spectrum of Thyroid Lesions on Cytology in a Secondary Care Centre, Karkala, Karnataka

Fine Needle Aspiration Cytology (FNAC) is a cost effective, minimally invasive procedure with less complications. It can be used in the diagnosis of thyroid lesions, aiding the clinician in the patient management and reducing the incidence of unnecessary surgeries. Thyroid profile test, ultrasonography and radionuclide scan are used as adjuvant diagnostic modalities.

Management of pediatric thyroglossal duct cyst: A case report

Introduction: Thyroglossal duct cysts are common congenital neck anomalies in children, diagnosed through clinical assessment and ultrasound, and treated with the Sistrunk procedure to prevent complications like infection and malignancy. Case Description: We present a case of a 4-year-old male patient with a progressively enlarging neck mass for three months. The mass was asymptomatic, did not cause any eating difficulties, and moved upwards during swallowing and tongue protrusion. Upon physical examination, a soft, mobile, cystic mass approximately 3 cm in diameter was identified beneath the hyoid bone. Supporting examinations, including ultrasound and fine-needle aspiration cytology, led to the diagnosis of a thyroglossal duct cyst. The patient underwent a successful Sistrunk procedure, which involved the excision of the cyst along with a portion of the hyoid bone. Postoperative management included administration of intravenous antibiotics and paracetamol, culminating in a full recovery without any signs of infection. The patient exhibited complete wound healing within two weeks. There was no evidence of cyst recurrence during a follow-up examination six months later. Conclusion: Despite being common, thyroglossal duct cysts require thorough evaluation to avoid misdiagnosis, and are typically identified by a slowly growing midline neck mass that moves with swallowing and tongue protrusion, often near the hyoid bone.

Bias in Evaluating Trends of Thyroid Cancer Incidence between Rural and Urban Populations

Abstract Background Diagnosis of thyroid cancer is based on fine needle aspiration cytology of thyroid nodules, based on nodules’ sonographic appearance and size. The American Thyroid Association published new guidelines for management of thyroid nodules in 2009 and 2015, where in some cases, only follow-up of thyroid nodules without any other procedure is recommended. This may lead to a decrease in diagnosed thyroid cancer cases. We studied thyroid cancer trends in Israel between the Arab population who are more likely to be living in rural areas, and the Jewish population who predominantly living in urban areas, and assesses whether these guidelines were reflected in the trends. Methods Data on new thyroid cancer cases were retrieved for Jews and Arabs separately from the Israel National Cancer Registry. Trends in age standardized incidence rates between 1996-2019 were evaluated for the two population groups using joinpoint regression model. Population group was included in the regression models to compare the trends between the two groups. We also studied trends in treatment of thyroid cancer at Rambam Health Care Campus. Results In both populations, age standardized thyroid cancer incidence rate increased between 1996 and 2013. However, between 2013-2019, Annual Percentage Change continuously increased in Arabs, but decreased in Jews. In the hospital study, we found that the Arab patients were 30% more likely to have surgery for small tumors. Conclusions The decrease in thyroid cancer incidence in the Jewish population compared with the Arab population may be related to differences in implementing the 2009 guidelines, which do not recommend fine needle aspiration cytology for very small tumors. We have found evidence that these guidelines were not followed to the same extent among Arab community clinics. This may explain the persisting increasing trend among Arabs, and could be one of the possible explanations for the differences in trends between the two groups. Key messages • Updated Guidelines regarding thyroid cancer diagnosis may be differently implemented by rural and urban populations. • Trends assessment may be biased due to differences in guidelines implementation.

The accuracy of fine needle aspiration cytology and ultrasonography in assessing thyroid nodules in correlation with histopathology: a retrospective study

Background: Accurately diagnosing thyroid nodules is vital for preventing unnecessary surgeries and providing prompt therapy. Although fine needle aspiration cytology (FNAC) and ultrasonography (US) are widely used diagnostic methods, their reliability is questioned. This study investigates the effectiveness of US and FNAC in thyroid nodule diagnosis and differentiates benign from malignant nodules in relation to final histopathological diagnosis. Method: A retrospective study including 307 adult patients with thyroid diseases who underwent neck US and FNAC before surgery was conducted between April 2019 and May 2023. The diagnostic efficacy of US, FNAC, and their combination usage was compared to histopathological results. Result: Histopathological findings revealed that 187(61%) cases were benign, while 120 (39%) were malignant. The US features of “taller-than-wider” forms and hypoechoic appearance had the highest diagnostic accuracy in characterizing malignant thyroid nodules, with 83% and 73% accuracy, respectively. The combination of US parameters demonstrated high sensitivity, specificity, positive predictive value, and negative predictive value (NPV) of 88.33%, 63.10%, 60.6%, and 89.4%, with a statistically significant area under the ROC curve (AUC: 0.828, P<0.001) than individual parameters. FNAC’s sensitivity, specificity, PPV NPV, and accuracy in detecting malignant lesions were 50%, 95%, 86%, 75%, and 77%, respectively, with acceptable discrimination and statistical significance (AUC: 0.723, P<0.0001). The combination of US parameters and FNAC significantly improved the AUC value (AUC: 0.878, P<0.0001), sensitivity (83.33%), and specificity (79.14%). Univariate analysis showed that hypoechoic appearance, heterogenicity, large mass size (>4 cm), “taller-than-wider,” infiltrative margins, and microcalcifications were risk factors for malignancy in thyroid nodules and were statistically significant (all P values <0.05). Conclusion: Combining US characteristics with FNAC results can afford the maximum analytical accuracy in distinguishing benign from malignant thyroid nodules. This strategy is practical due to its simplicity, minimal invasiveness, and cost-effectiveness, enabling robust management regimens and avoiding additional surgical procedures.

Intraparotid Facial Nerve Schwannoma - A Case Report

Abstract Rationale: Intraparotid facial nerve schwannoma (IPFNS) is a rare entity. Diagnosing these tumours is challenging as multiple differential diagnoses exist for swellings in the infraauricular region. Delay in diagnosis can lead to adverse outcomes. Patient Concerns: A 27-year-old female presented with swelling over the left infraauricular region, which concerned her cosmetic appearance. Diagnosis: It was initially misdiagnosed with imaging techniques computerised tomography (CT scan) and fine-needle aspiration cytology, leading to a diagnostic dilemma. Treatment: Superficial parotidectomy was planned and intraoperatively, a cystic lesion was seen adherent to the temporal branch of the facial nerve, which was resected along with the nerve branch. Histopathology confirmed the diagnosis as facial nerve schwannoma. Outcomes: The patient’s cosmetic concern was resolved but there was loss of wrinkles over the ipsilateral forehead region. No recurrence was seen. Take-Away Lessons: IPFNS often causes a diagnostic dilemma and an appropriate and timely diagnosis is required to decrease the morbidity and undertreatment.

Diagnostic sensitivity of fine-needle aspiration cytology in thyroid cancer

Introduction Fine-needle aspiration cytology (FNAC) is an effective tool in the diagnostic work-up of patients with thyroid nodules. The aim of our study was to assess the diagnostic sensitivity of FNAC in thyroid cancer (TC) in Sweden by correlating the findings of preoperative FNAC with those obtained through final histology of the surgical specimen. Methods A Swedish nationwide cohort of patients having surgery for TC (n = 2519) from the Scandinavian Quality Register for Thyroid, Parathyroid and Adrenal surgery between 2004 and 2013 was obtained. Data was validated through scrutinizing patient FNAC and histology reports. Results Among the 2519 cases operated with a final diagnosis of TC, the diagnosis was substantiated and validated through the histology report in 2332 cases (92.6%), included in the present study. Among these, 1679 patients (72%) were female and the median age at TC diagnosis was 52.3 years (range 18-94.6). In 353 cases (15.1%) FNAC was not performed at all; whereas in the remaining 1965 cases, the diagnostic sensitivity of FNAC was 81.6%. In lesions > 1 cm, FNAC diagnostic sensitivity reached 86.5%, whereas in lesions < 1 cm, FNAC yielded a sensitivity of 61.5%. Approximately 85% of FNACs (n = 1981/2332) were performed using ultra-sonographic (US) guidance. In TC lesions > 1 cm, the diagnostic sensitivity of US-guided FNAC (n = 1504) was 86.9% as compared to 76.9% in clinically applied FNAC without US utilization (n = 118). Conclusions FNAC is performed in most patients operated for TC in Sweden (85%) and retains its value as a tool in TC diagnostic work-up with an overall sensitivity of 82%, reaching 87% in lesions > 1 cm, that harbor clinically relevant TC.

Cytological Evaluation of Palpable Non-Neoplastic Breast Lesions among Women attended from Rural Community of Bangladesh: A Retrospective Cross-Sectional Study

Background: Non-neoplastic palpable breast disease is one of the most common disorders from which women suffer throughout the world. The use of fine-needle aspiration cytology (FNAC) method has proven to be quick, simple and cost-effective with minimum risk of complications in the evaluation of breast lumps. Objective: This study was planned to find out the common causes of various types of non-neoplastic breast lesions of female at different ages through fine needle aspiration cytology. Methodology: The retrospective cross-sectional study was carried out in the Department of Pathology at Monno Medical College&amp; Hospital, Manikganj, Bangladesh. It lasted 2 years 6 months from July 1, 2019 to December 31, 2021. This study examined all breast lumps found in female patients. For data analysis, the patient's age and FNAC report were recorded. Aspirates were done using 5ml/10ml syringe and 23-gauge needle. Smears were stained with Papanicolaou stain. Results: The study included total 349 female patients with breast lesion. Among these, non-neoplastic lesions were 183(52.44%) cases and neoplastic lesions were 166(47.56%) cases. Among the lesions, 105(30.08%) cases were in fibrocystic changes; 28(8.02%) cases were in non-suppurative mastitis; 24(6.87%) cases were in suppurative mastitis (abscess), 14(4.01%) cases were in granulomatous mastitis. About 45(42.88%) cases of Fibrocystic changes, 13(44.84%) cases of non-suppurative mastitis and 9(37.5%) cases of Suppurative mastitis (abscess) were in the age group 21 to 30 years, 21 to 30 years and 41 to 50 years respectively. Conclusion: Fibrocystic changes are the commonest lesion in this study. Journal of Monno Medical College June, 2024; 10 (1):07-12

Malignant Peripheral Nerve Sheath Tumor of the Pancreas with Molecular Confirmation: A Case Report with Comprehensive Histopathologic and Molecular Characterization

Abstract Introduction/Objective Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft tissue sarcomas arising from a peripheral nerve or exhibiting nerve sheath differentiation. They are often associated with neurofibromatosis type 1, and most often arise in the trunk, extremities, or head and neck region. In patients without neurofibromatosis type 1, sporadic de novo or radiotherapy-associated MPNSTs can pose a diagnostic challenge. MPNSTs arising from visceral organs are exceedingly rare. Here we report a case of MPNST arising in the pancreas. Methods/Case Report The patient is a 75-year-old female, MUTYH mutation carrier, with prior history of breast and bladder cancers, each treated with respective local excision and radiation therapy. Magnetic resonance imaging (MRI) performed for pancreatic cancer screening showed a 4.7 cm heterogeneous mass in the pancreatic tail suggestive of pancreatic neoplasm. Fine needle aspiration cytology was non-diagnostic. However, due to the radiologic concern for malignancy, the patient proceeded with surgical resection by distal pancreatectomy with splenectomy. Macroscopically, a 6.5 cm, tan-white, partially necrotic mass was identified in the pancreatic tail. Microscopic examination showed a spindle cell neoplasm arranged in a vague fascicular fashion with moderate nuclear pleomorphism, geographic necrosis, and frequent mitotic figures (15 per 10 high power fields). Fifteen lymph nodes were negative for metastasis. The tumor was confined to the pancreas grossly and microscopically. Immunohistochemical stains showed the neoplastic spindle cells to be positive for TLE1 (diffuse) and S100 (patchy), while negative for SOX10, CD117, DOG1, desmin, actin, MyoD1, ERG, STAT6, and ALK1. In addition, H3K27me3 showed loss of nuclear expression. Next generation sequencing (NGS) revealed gene mutations in NF1, TP53, PIK3CA, and PTEN, and copy number losses involving CDKN2A and CDKN2B. Genome-wide DNA methylation analysis was performed which revealed copy number losses of CDKN2A/B and gains of PTCH1 and MDM2. However, the Sarcoma DNA Methylation Classifier did not provide any diagnostic matches. Overall, the morphologic features, loss of H3K27me3 expression, presence of NF1 and TP53 mutations, and copy number losses in CDKN2A/B supported a diagnosis of high-grade MPNST. The patient has been followed clinically without adjuvant therapy. Results (if a Case Study enter NA) N/A Conclusion We report an extremely rare case of MPNST of the pancreas with molecular confirmation.

A rare case report of hurthle cell adenoma mimicking malignancy

Thyroid lesions are the most common endocrine diseases, occurring in usually all age groups, though accurate diagnosis still remains a challenge, as due to oncocytic potentials of Thyroid cells leads to like indeterminate or suspicious diagnosis. Long standing benign Thyroid lesion shows atypical presentation suspicious to malignancy. Now a days with the help of WHO classification and available advanced diagnostic measures helping to confirm the diagnosis, avoiding overdiagnosis and wrong treatment. Hence this study review the importance of Histopathological study with coordination with immunohistochemistry (IHC) study, where suspicious thyroid malignant lesion finally diagnosed as benign Hurthle cell/ Oncocytic adenoma in Nodular Goitre.: 72 year old female presented huge neck swelling since one year, was reviewed in our departments of Pathology and ENT. Fine needle aspiration cytology (FNAC) features are suspicious of Malignancy, further Histopathological features were studied with co ordance of IHC study. FNAC features, which were suspicious of Malignancy were further studied with Histopathological and IHC studies diagnosed as Hurthle cell/ Oncocytic adenoma in Nodular Goitre. Histopathology remains the cornerstone for the diagnosis of thyroid oncocytic lesions and also in distinguishing between adenoma and carcinoma.

Case Report : Undifferentiated Synovial Sarcoma Presenting as a Large Thoracic Mass: A Rare and Challenging Diagnosis

Background: Undifferentiated synovial sarcoma (USS) is a rare and aggressive subtype of soft tissue sarcoma. Its presentation as a large thoracic mass poses significant diagnostic and therapeutic challenges.  Case Presentation: A 34-year-old male presented with a three-month history of progressive chest pain and hemoptysis. Imaging studies revealed a large, cystic thoracic mass with pleural effusion. Initial serological testing suggested hydatid cyst, but subsequent testing revealed negative Echinococcus (Hydatid) IgG antibodies.  Diagnostic and Therapeutic Interventions: Repeat fine-needle aspiration cytology (FNAC) was deferred due to revised ultrasound findings indicating a solid fibrocystic vascular lesion. Bronchial artery embolization (BAE) was performed to control life- threatening hemorrhage. Thoracotomy and en-bloc mass excision were subsequently undertaken.  Histopathological Diagnosis: Histopathological examination of the resected specimen revealed undifferentiated synovial sarcoma and spindle cell sarcoma.  Clinical Implications: This case highlights the importance of correlating imaging and serological findings, managing vascular complications, and the efficacy of BAE in controlling hemorrhage. The significance of thoracotomy and mass excision in achieving diagnostic clarity and therapeutic success is underscored.  Conclusion: Undifferentiated synovial sarcoma presenting as a large thoracic mass poses significant diagnostic and therapeutic challenges. A multidisciplinary approach, incorporating imaging, serological testing, and surgical intervention, is crucial for achieving optimal patient outcomes.

Early Diagnosis of Papillary Carcinoma in a Thyroglossal Duct Cyst: A Multidisciplinary Approach and the Crucial Role of Fine-Needle Aspiration Cytology

Early Diagnosis of Papillary Carcinoma in a Thyroglossal Duct Cyst: A Multidisciplinary Approach and the Crucial Role of Fine-Needle Aspiration Cytology

Diagnostic Accuracy of Bethesda Classification of Thyroid Nodules at a Kenyan Hospital: A Retrospective Study

Background: The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) was developed to standardize the reporting of thyroid nodule fine-needle aspiration cytology (FNAC) results. The adoption of TBSRTC is based on the implied risk of malignancy per category, but this has shown wide variation in different regions worldwide. Aim: The aim of this study is to determine the diagnostic accuracy of the Bethesda classification of thyroid nodules in a Kenyan hospital. Methods: A retrospective longitudinal study examined FNAC and histopathology data of thyroid gland nodules at a Kenyan hospital from 2010 to 2019; specimens from 347 patients were found. An analysis was performed to determine the diagnostic accuracy of the Bethesda classification in detecting malignancy among these patients. Results: The malignancy rate was 16.1%. The risk of malignancy as per the Bethesda category was as follows: non-diagnostic— 19.6%, benign—6%, atypia of undetermined significance—20%, follicular neoplasm—16.7%, suspicious for malignancy—80%, and malignant—85.7%. The diagnostic properties of FNAC defining “malignant” and “suspicious for malignancy” categories as malignant were as follows: sensitivity—64.7%, specificity—97.6%, and accuracy—92.7%. Conclusion: The Bethesda classification had high diagnostic accuracy, with the risk of malignancy consistent with the Bethesda findings. Classifying malignancy as “malignant” and “suspicious for malignancy” yielded the most favorable diagnostic properties for FNAC.

Evaluation of ACR TI-RADS for Predicting Malignancy in Thyroid Nodules: Insights from Fine-Needle Aspiration Cytology and Histopathology Results

Evaluation of ACR TI-RADS for Predicting Malignancy in Thyroid Nodules: Insights from Fine-Needle Aspiration Cytology and Histopathology Results

Diagnostic value of FNA, ultrasound elastography and CEUS in thyroid carcinoma

Background: To investigate the role of fine needle aspiration cytology (FNA), sonoelastography and contrast-enhanced ultrasound (CEUS) in the diagnosis of thyroid carcinoma. Methodology: A total of 150 patients with suspected thyroid cancer admitted to our hospital from January 2019 to December 2021 were selected and divided into group A, group B and group C according to random number table, with 50 cases in each group. FNA was used in group A, ultrasound elastography was used in group B, and CEUS was used in group C. Pathological diagnosis was performed in all patients, and the diagnostic sensitivity, specificity, and accuracy were compared among the three groups. Results: The diagnostic sensitivity, specificity and accuracy of FNA in group A were 90.91%, 70.59% and 84.00%, respectively; the diagnostic sensitivity, specificity and accuracy of ultrasound elastography in group B were 94.12%, 81.25% and 90.00%, respectively; the diagnostic sensitivity, specificity and accuracy of CEUS in group C were 88.57%, 73.33% and 84.00%, respectively; the three groups were compared (P &gt; 0.05). Conclusion: All three diagnostic techniques had a relatively high sensitivity and accuracy in the diagnosis of thyroid carcinoma. Ultrasound elastography had the highest sensitivity and specificity among the three techniques, while FNA and CEUS had similar diagnostic performance. Keywords: Fine needle aspiration cytology; ultrasound elastography; contrast-enhanced ultrasound; thyroid cancer; diagnostic efficacy.

6641 Observation in Lieu of Surgical Management in Hurthle Cell Neoplasm: Role of Thyroseq V3 Molecular Testing

Abstract Disclosure: R. Kaur: None. L. Kaur: None. T. Chaudhary: None. M. Shrivastava: None. N. Patel: None. The diagnostic utility of fine needle aspiration biopsy with cytology is often confounded in thyroid nodules with predominance of hurthle cells, often interpreted as an oncocytic/hurthle cell lesion with intermediate risk of malignancy, bethesda category (BC) III or IV. With the advent of molecular testing like thyroseq V3, it is helpful in ruling out substantial risk of cancer and considering observation in lieu of surgical management in such difficult cases. We present a case of a 75 year old woman with past medical history significant for type 2 diabetes mellitus and hypothyroidism who was found to have a left lobe complex nodule within a non-toxic multinodular goiter In 2022. Ultrasound of the neck showed a 1.6 x 1.8 x 2 cm intermediate nodule, followed by a fine needle aspiration biopsy which was non-diagnostic and reported as benign, showing only cystic contents and insignificant follicular cells, Bethesda class II. Follow up for the nodule was recommended in one year. Repeat Imaging one year later revealed left nodule without significant changes and repeat fine needle aspiration cytology was advised. The biopsy result was reported as an oncocytic/ Hurthle cell neoplasm, Bethesda class IV. The specimen was also submitted for thyroseq molecular testing and results were awaited. The patient was euthyroid with negative anti thyroid antibodies. There was no family history of thyroid cancer or radiation exposure. The patient denied any active symptoms like shortness of breath, neck pain or pressure, recent voice changes, dysphasia, loss of appetite or weight .On examination the patient was found to have a left thyroid nodule with no signs of tracheal deviation. CT scan of the neck demonstrated a left thyroid nodule with no compression. The patient was followed by both endocrinology and oncology and surgical options were discussed depending upon the biopsy results while awaiting molecular testing report. Molecular testing with thyrosec V3 revealed an absence of gene mutations and reported a low probability of cancer. Depending upon the results observation was considered in lieu of surgical management. Hence It was decided to keep the patient under observation considering the molecular test results in conjunction with all relevant imaging, clinical findings, symptoms, patients family history as well as patients preference. This case report demonstrates the crucial role of molecular Diagnostics specifically thyroseq V3 in the often difficult clinical management of hurthle cell thyroid nodules for ruling out surgical management. Thyroseq V3 shows reliable performance in Hurthle cell cancers with sensitivity of 93% and specificity of 69%. In times of patient guided decision making and ability to narrow down the need of surgery based on pre-operative fine needle aspiration cytology, molecular profiling of thyroid nodules has become increasingly utilized. Presentation: 6/1/2024

6913 Clinical Prognosis in Patients with Thyroid Nodules Expressing PPAR-Gamma Gene Fusion on Thyroid FNA Cytology

Abstract Disclosure: R. Hammoudeh: None. E. Morariu: None. A. Wald: Other; Self; Technical consultant to Sonic Healthcare USA.. W.R. Doerfler: None. Y. Linwah: None. M. Nikiforova: Owner/Co-Owner; Self; Owner of intellectual property related to ThyroSeq, receive royalties through the University of Pittsburgh; consultants for Sonic Healthcare USA. Y.E. Nikiforov: Owner/Co-Owner; Self; Owner of intellectual property related to ThyroSeq, receive royalties through the University of Pittsburgh; consultants for Sonic Healthcare USA. Background: PPARG rearrangements, typically PAX8-PPARG, are common genetic alterations in follicular thyroid carcinoma and follicular variant of papillary thyroid carcinoma (FVPTC). Most tumors appear to be indolent, however distant metastasis has been reported. The aim of this study was to determine the prevalence and type of malignancy in a series of thyroid nodules positive for PAX8 rearrangement in thyroid fine-needle aspiration (FNA) samples. We also aimed to evaluate the impact on patient management, prognosis and outcomes. Methods: Thyroid nodules positive for PAX8 fusion on ThyroSeq v2 and v3 genomic classifier testing of FNA samples from May 2008 to February 2022 were identified. Clinical data was obtained by retrospective chart review. Results: Overall, 44 nodules positive for PAX8/PPARG fusion were identified. None of these nodules expressed additional genetic mutations on molecular testing. Surgical pathology was available for 40 patients, which identified 35 (87.5%) malignant, 3 NIFTP (7.5%), and 2 benign (5%) lesions. In the malignant group, FNA cytology revealed 1 (2.8%) benign, 13 (37.1%) AUS/FLUS, 12 (34.2%) suspicious for SFN/FN, 5 (14.3%) suspicious for PTC and 4 were not classified. In the non-malignant group, FNA cytology revealed 2 (40%) benign, 2 (40%) AUS/FLUS, 1 (20%) SFN/FN. With regards to surgical intervention, 30 (75%) patients had total thyroidectomy and 10 (25%) underwent lobectomy, of which 8 were followed by completion thyroidectomy. Among the malignant and non-malignant groups, there was no difference in sex (82.8% vs 100% female, p=1), age (43.6 vs 50.2 years, p=0.2), or tumor size on surgical pathology (3.26 vs 4 cm, p=0.23). In the malignant group, histology showed 30 (85.7%) FVPTC, 2 (5.7%) conventional PTC, 2 (5.7%) follicular carcinoma and 1 (2.9%) solid variant PTC. Of the FVPTC group, 9 had oncocytic cell features, 3 focal solid patterns, and 1 showed focal solid growth and progression to poorly differentiated thyroid carcinoma. Only 1 showed lymphatic invasion, 10 showed angioinvasion. Following the ATA thyroid cancer risk stratification, 23 (65.7%%) had low risk, 9 (25.7%) intermediate risk and 3 (8.6%) high risk. 18 patients in the malignant group underwent RAI ablation. Average follow up for the malignant nodules was 49.7 months (0-170). 1 had suspected recurrence on thyroid ultrasound after a year. No evidence of distant metastasis was documented. Conclusions: The majority of thyroid nodules with PAX8/PPARG rearrangement found on FNA were cancers, predominantly follicular variant PTC, and some were benign or NIFTP. The majority were low risk, but intermediate and high-risk cancers with more aggressive histology, angioinvasion, and poorly differentiated cancer were also identified. While only one recurrence was identified on short follow-up, longer follow-up duration is required for better understanding the behavior of these tumors. Presentation: 6/3/2024

6477 Surprise Finding For A Thyroid Nodule: Metastatic Renal Cell Carcinoma

Abstract Disclosure: A. Xu: None. E. Hsu: None. Introduction: A patient with an incidental and asymptomatic thyroid nodule underwent fine needle aspiration biopsy (FNA) after the nodule increased in size. Without a definite pathology after three FNA attempts, thyroidectomy was performed, where pathology found metastatic renal cell carcinoma (RCC). Clinical Case: A 64 year old woman had a past medical history of obesity, type 2 diabetes, RCC (stage I: pT1bN0M0) treated with right radical nephrectomy five years prior and thought to be in remission, remote smoking history smoking, and coronary artery disease with coronary artery bypass graft (CABG) two months prior, on anticoagulation. The patient reported a distant history of right thyroid lobectomy over a decade prior for unclear reasons, but she was adamant that the pathology was benign. Two years prior to presentation, CT chest done for RCC surveillance had detected a left thyroid nodule. Ultrasound at the time revealed a 3.6 x 1.9 x 2.3 cm solid, isoechoic nodule in the upper left lobe, which was not taller than wide, and had smooth margins and no echogenic foci. A repeat ultrasound at the time of presentation showed interval growth of the nodule, now measuring 4.3 x 2.1 x 2.9 cm. FNA was unsatisfactory, yielding predominantly blood. Patient felt well and had no compressive neck symptoms. We opted to wait two months and repeat FNA, which resulted as atypia of undetermined significance - Bethesda category III (AUS). We recommended completion thyroidectomy, but patient preferred to avoid surgery. We decided to wait two months and repeat FNA with molecular testing. This third FNA resulted AUS again; however, due to non-medical reasons, molecular testing was not performed. Another ultrasound showed slight growth of the nodule, 5.1 x 2.9 x 2.0 cm, which appeared hypoechoic now, but was still not taller than wide, with smooth margins and no echogenic foci. Completion thyroidectomy was performed, with pathology showing metastatic clear cell renal cell carcinoma. Immunostains were positive for carbonic anhydrase and renal cell carcinoma marker and negative for TTF-1. Whole-body PET-CT showed no hypermetabolic foci, and a repeat PET-CT one year later still showed no evidence of metastatic disease. Other than a hospitalization for COVID-19, patient is doing well and asymptomatic now over a year after her thyroidectomy. Oncology will continue routine surveillance imaging for her metastatic renal cell carcinoma thought to be in remission. Clinical Lessons: This case of metastatic renal cell carcinoma to the thyroid adds to the small body of literature showing the thyroid as a possible site of RCC metastasis. The long time interval between initial RCC presentation and metastasis to the thyroid makes this diagnosis more difficult; however, clinicians should be aware of the possibility, making thyroidectomy a stronger option in cases where FNA cytology is indeterminate. Presentation: 6/2/2024

6477 Surprise Finding for a Thyroid Nodule: Metastatic Renal Cell Carcinoma

Abstract Disclosure: A. Xu: None. E. Hsu: None. Introduction: A patient with an incidental and asymptomatic thyroid nodule underwent fine needle aspiration biopsy (FNA) after the nodule increased in size. Without a definite pathology after three FNA attempts, thyroidectomy was performed, where pathology found metastatic renal cell carcinoma (RCC). Clinical Case: A 64 year old woman had a past medical history of obesity, type 2 diabetes, RCC (stage I: pT1bN0M0) treated with right radical nephrectomy five years prior and thought to be in remission, remote smoking history smoking, and coronary artery disease with coronary artery bypass graft (CABG) two months prior, on anticoagulation. The patient reported a distant history of right thyroid lobectomy over a decade prior for unclear reasons, but she was adamant that the pathology was benign. Two years prior to presentation, CT chest done for RCC surveillance had detected a left thyroid nodule. Ultrasound at the time revealed a 3.6 x 1.9 x 2.3 cm solid, isoechoic nodule in the upper left lobe, which was not taller than wide, and had smooth margins and no echogenic foci. A repeat ultrasound at the time of presentation showed interval growth of the nodule, now measuring 4.3 x 2.1 x 2.9 cm. FNA was unsatisfactory, yielding predominantly blood. Patient felt well and had no compressive neck symptoms. We opted to wait two months and repeat FNA, which resulted as atypia of undetermined significance - Bethesda category III (AUS). We recommended completion thyroidectomy, but patient preferred to avoid surgery. We decided to wait two months and repeat FNA with molecular testing. This third FNA resulted AUS again; however, due to non-medical reasons, molecular testing was not performed. Another ultrasound showed slight growth of the nodule, 5.1 x 2.9 x 2.0 cm, which appeared hypoechoic now, but was still not taller than wide, with smooth margins and no echogenic foci. Completion thyroidectomy was performed, with pathology showing metastatic clear cell renal cell carcinoma. Immunostains were positive for carbonic anhydrase and renal cell carcinoma marker and negative for TTF-1. Whole-body PET-CT showed no hypermetabolic foci, and a repeat PET-CT one year later still showed no evidence of metastatic disease. Other than a hospitalization for COVID-19, patient is doing well and asymptomatic now over a year after her thyroidectomy. Oncology will continue routine surveillance imaging for her metastatic renal cell carcinoma thought to be in remission. Clinical Lessons: This case of metastatic renal cell carcinoma to the thyroid adds to the small body of literature showing the thyroid as a possible site of RCC metastasis. The long time interval between initial RCC presentation and metastasis to the thyroid makes this diagnosis more difficult; however, clinicians should be aware of the possibility, making thyroidectomy a stronger option in cases where FNA cytology is indeterminate. Presentation: 6/2/2024

7639 A Rare Cause of Lung Adenocarcinoma with Metastasis to the Thyroid

Abstract Disclosure: E. Echevarria-Torres: None. C.G. Yap: None. K.E. Izuora: None. A rare cause of lung adenocarcinoma with metastasis to the thyroid. Metastasis to the thyroid gland from non-thyroid malignancies is rare. When metastasis occurs, presenting symptoms are typically nonspecific, representing a diagnostic challenge. With the goal of raising awareness, we present a case of lung adenocarcinoma with metastasis to the thyroid. An 85-year-old man with a history of hypertension, hyperlipidemia and 60 years smoking history presented to the endocrine clinic for evaluation of subclinical hyperthyroidism. On the physical exam, there was fullness in the right thyroid area which on ultrasound showing a large right thyroid nodule occupying the entire lobe. There was also a solid 4.5 cm x 3.4 cm x 4.6 cm nodule in the mid-anterior left thyroid lobe. Fine needle aspiration cytology of right nodule revealed malignant cells and cell block material positive for TTF-1 (Thyroid Transcription Factor 1) concerning for malignancy. The left thyroid nodule cytology was consistent with benign follicular nodule. Chest CT ordered for surgical planning showed right upper lobe pleural-based lung opacity measuring 3.7 cm x 2.9 cm with supra clavicular lymphadenopathy. Biopsy of lung mass and supra clavicular lymph nodes revealed primary lung adenocarcinoma involving the lymph nodes consistent with stage Iva (cT3NxM1b). The patient was referred to oncology for further management. Discussion: Metastatic lesions to the thyroid gland account for less than 1 % of all malignant thyroid tumors with most cases found on autopsy. This is hypothesized to be due to the rich blood supply and high iodine content of the thyroid gland. Thyroid metastasis usually presents several years after initial diagnosis and treatment of non- thyroid malignancy. Patients can present with enlarging thyroid nodules, neck swelling, dysphagia and, in rare instances, upper airway obstruction. We present a rare case of lung cancer with metastasis into the thyroid. The thyroid nodule initially palpated upon physical exam led to eventual thyroid ultrasound and subsequently to his diagnosis of lung adenocarcinoma after findings of lung nodule which was biopsied and showed primary lung adenocarcinoma. TTF-1 was also positive which is typically expressed by lung adenocarcinomas. Treatment for thyroid metastasis is surgery, along with treatment of primary malignancy. The earlier the diagnosis and treatment the more favorable the prognosis. Radiotherapy and chemotherapy are other means to reduce the recurrence. Thyroid hormone replacement will be warranted post operatively for hypothyroidism. We present this uncommon case to raise awareness about the presentation of thyroid metastasis to enhance timely diagnosis and intervention. Presentation: 6/1/2024