Metastatic Papillary Thyroid Carcinoma Research Articles

Snail-1 Overexpression Correlates with Metastatic Phenotype in BRAFV600E Positive Papillary Thyroid Carcinoma.

The ability of cancer to metastasize is regulated by various signaling pathways, including transforming growth factor β (TGFβ), also implicated in the upregulation of Snail-1 transcription factor in malignant neoplasms. B-type Raf kinase gene (BRAF)V600E, the most common driving mutation in papillary thyroid carcinoma (PTC), induces epithelial to mesenchymal transition (EMT) in thyroid cancer cells through changes in the Snail-1 level, increasing cell migration and invasion. However, little is known about the mechanism of Snail-1 and BRAFV600E relations in humans. Our study included 61 PTC patients with evaluated BRAFV600E mutation status. A total of 18 of those patients had lymph node metastases—of whom 10 were BRAFV600E positive, and 8 negative. Our findings indicate that the expression of Snail-1, but not TGFβ1, correlates with the metastatic phenotype in PTC. This is the first piece of evidence that the upregulation of Snail-1 corresponds with the presence of BRAFV600E mutation and increased expression of Snail-1 in metastatic PTC samples is dependent on BRAFV600E mutation status.

Study of metastatic malignancy in fine needle aspiration cytology of lymph nodes

Introduction: Fine Needle Aspiration Cytology (FNAC) of the lymph node is a widely applied technique for rapid and accurate diagnosis. It is minimally invasive, cost effective and widely accepted technique. Aims and objectives: Categorization of various metastatic malignancies diagnosed on FNAC of lymph nodes and their correlation with addiction. Materials and methods: Conducted on patients attending the cytopathology section of Pathology department of B. J Medical College, Ahmedabad in between January 1st, 2019 and August 31st, 2019. Addiction history was obtained in each case. Results: Out of 60 cases, 35 cases show metastatic squamous cell carcinoma, 14 cases show metastatic poorly differentiated carcinoma, 6 cases show metastatic breast carcinoma, 3 cases show metastatic adeno carcinoma, 1 case show metastatic necrotizing squamous cell carcinoma and 1 case show metastatic papillary carcinoma of thyroid. Conclusion: FNAC is a minimally invasive, cost effective and quick method of diagnosing malignant involvement of draining lymph nodes which helps the clinician plan management of patients more effectively.

Advanced papillary thyroid carcinoma responding to nivolumab

Clinical indications of immune checkpoint inhibitors have expanded to a variety of malignancies. Approximately one in six patients with hepatocellular carcinoma respond to programmed death 1 inhibitors nivolumab and pembrolizumab. We report herein a patient with synchronous metastatic hepatocellular carcinoma and advanced papillary thyroid carcinoma treated with nivolumab in the second-line therapy.Management and outcome: The hepatocellular carcinoma showed a durable response to the second-line agent nivolumab. Remarkably, the patient's papillary thyroid carcinoma also responded to this programmed death 1 inhibitor. To our knowledge, this is the first case report showing the efficacy of nivolumab in the treatment of metastatic papillary thyroid carcinoma. Further studies with immune checkpoint inhibitors in papillary thyroid carcinoma seem warranted.

MON-447 Schwannoma Masquerading as Metastatic Papillary Thyroid Carcinoma in a Cervical Lymph Node

Background: Schwannomas originate from peripheral nerve sheath Schwann cells and develop in various locations, commonly seen in the head and neck in up to 45% of cases. On ultrasound, they appear hypoechoic, lack a hilum, and can resemble a metastatic lymph node in patients with thyroid cancer. We describe a case of a schwannoma masquerading as metastatic papillary thyroid carcinoma. Clinical Case: A 59-year-old woman presented to our clinic with a history of Graves’ disease and papillary thyroid cancer (PTC) for which she underwent surgery over fifteen years ago at an outside institution. Pathology revealed two microfoci of PTC (0.5 and 0.4 cm) and 0 of 3 positive lymph nodes, with no other concerning features. She underwent radioactive iodine therapy (RAI) with 100 mCi postoperatively. There was no evidence of metastasis on her post-treatment scan. She had surveillance including neck ultrasounds with no evidence of recurrence. Five years later, neck ultrasound revealed a 5 mm nodule in the right neck posterior to the jugular vein. This nodule remained stable a year later and was not mentioned on subsequent ultrasounds. Two years ago upon presentation to our institution, she was found to have a suspicious hypoechoic solid mass on neck ultrasound. It was located in the lateral neck deep to the internal jugular vein and immediately adjacent and lateral to the common carotid and measured 8 x 7 x 7 mm enlarging to 13 x 9 x 10 mm in the next year. On one of the ultrasounds, the mass was noted to be inseparable from the surrounding nerve fibers and the possibility of nerve sheath tumor was suggested although a metastatic lymph node could not be excluded. This nodule enlarged to 13 x 9 x 10 mm in the next year. Due to the location, biopsy was deemed difficult and she underwent surgical resection of the mass. Intraoperatively, the lesion was noted to be very firm and intimately involved with the vagus nerve, which had to be sacrificed as it could not be dissected off. Pathology revealed a schwannoma, which was confirmed by immunohistochemical staining. Conclusion: This case highlights the importance of recognizing subtle but important ultrasonographic features of a schwannoma in the neck as it can resemble a metastatic lymph node, especially in a patient with history of thyroid cancer. Clinicians should consider this in the differential diagnosis when there are appropriate imaging findings that may be consistent with a schwannoma, including homogeneous hypoechogeneity and nerve continuity.

MON-440 Unusual Case of Metastatic Struma Ovarii Diagnosed at the Time of Hysterectomy

Introduction: Struma ovarii is rare ovarian teratoma composed of more than 50% mature thyroid tissue, which can rarely transform to malignancy. There are fewer than 200 cases reported and no established treatment approach. We present a case of metastatic malignant struma ovarii. Case Presentation: A 41 year old female was diagnosed with metastatic papillary thyroid carcinoma (PTC) after it was found on uterine histopathology. History was notable for remote left ovarian cystectomy of a mature teratoma with prominent thyroid component. She had no personal or family history of craniocervical radiation or thyroid cancer. Eight years later, she had a total hysterectomy for menorrhagia. Pathology showed subcentimeter serosal deposits of follicular variant PTC, staining positive for thyroglobulin, CK19, and HBME1. Endometrial and cervical pathology were normal; the myometrium had many leiomyomata. Post-hysterectomy TSH was 2.3 (0.34 - 5.66 µIU/mL), and thyroglobulin 44.3 (<=33.0 ng/mL). Thyroid ultrasound showed a 7 mm isoechoic nodule without lymphadenopathy. Whole body PET/CT showed multiple hypermetabolic masses in the pelvic peritoneum and liver. The right ovary had many cystic lesions and was enlarged to 5.3 x 4.5 cm. She underwent partial hepatectomy, oophorectomy, salpingectomy, and omental resection with no residual disease. Pathology showed follicular variant PTC in both ovaries, peritoneum, colonic mesentery, and omentum. Thyroglobulin fell to 6.9 ng/mL 3 weeks later. A 0.2 cm focus of follicular variant PTC with capsular invasion was found on pathology after total thyroidectomy. She underwent radioiodine ablation with 150 mCi. Postablative scan showed residual activity in the thyroid bed and right hemipelvis, but no new foci of activity. CT abdomen showed resolution of perihepatic lesions and thyroglobulin declined further to 0.5 ng/mL. Discussion: A low risk of recurrence (7.5%) has been reported in patients with malignant struma ovarii, with survival rates of 96.7% at 5 years and 84.9% at 20 years, despite a variety of surgical and adjuvant management strategies. Unilateral cystectomy, unilateral salpingo-oophorectomy, or total abdominal hysterectomy and bilateral salpingo-oophorectomy may be sufficient for patients with well differentiated thyroid cancer arising in struma ovarii without metastases. Thyroid ultrasound should be performed to exclude primary thyroid malignancy. Patients with distant metastases may benefit from aggressive treatment including resection of gross abdominal and pelvic disease and total thyroidectomy to facilitate radioactive iodine ablation and surveillance for recurrence. Conclusion: Due to its rarity, there is no consensus on optimal treatment of malignant struma ovarii. More research in this field is warranted.

MON-453 Dramatic Clinical Response to Lenvatinib in a Pediatric Patient with Advanced Metastatic Papillary Thyroid Carcinoma

Introduction: Papillary thyroid cancer (PTC) is the most common thyroid tumor in childhood. Most patients are referred with locally advanced and/or distant disease at the time of diagnosis. Whenever possible, these patients should be offered total thyroidectomy and radioiodine remnant ablation; however, this approach is not always feasible, rendering these tumors unresectable. These critical cases could benefit from neoadjuvant treatment with multikinase inhibitors (MKI) so that standard treatment can be performed. Lenvatinib is an MKI recently approved in many countries throughout the world for the treatment of radioiodine refractory adult differentiated thyroid cancer. Only few pediatric cases have been reported. Case report: A 10-year-old female patient with locally advanced PTC and metastasis to the lungs, who required 3 liters of oxygen due to respiratory failure caused by bilateral miliary lung disease, mistakenly treated as tuberculosis two months previously and referred to our Hospital. A large thyroid mass adhered to deep tissues was confirmed on CT scan, showing a large heterogeneous neck mass with multiple microcalcifications associated with multiple lymph nodes. Both lungs had multiple micro-nodular disease with interstitial involvement. Total thyroidectomy together with lymph-node dissection was planned, but extensive local infiltration made the lesion unresectable and surgery was limited to a thyroid biopsy. The patient required respiratory assistance. Histopathology confirmed the presence of a PTC (diffuse sclerosing variant) with a RET-PTC3 oncogene rearrangement. Eight days after surgery the patient was critical and we decided to indicate the compassionate use of Lenvatinib. The patient was started on oral lenvatinib at a dose of 14 mg daily (14 mg/m/day). Three days later, she clinically improved and nine days post-lenvatinib initiation, the patient was discharged from hospital without need for oxygen therapy. Lab studies showed a rise in thyroglobulin levels in the first month of treatment followed by a significant drop. All Lung Function Test parameters significantly improved. The patient initially had severe restrictive breathing and due to the resting dyspnea with hypoxemia she could not perform the walking test. Two months after treatment onset she could walk 360 meters in six minutes with 96% oxygen saturation. After 4 months on Lenvatinib, imaging studies showed a stable thyroid mass while the pulmonary nodules appeared stable to slightly smaller without evidence of new or progressive disease. Conclusion: On lenvatinib treatment, our patient showed significant clinical improvement, arrest of disease progression, and stable disease on imaging studies. This case shows that lenvatinib may be a beneficial option for children with advanced PTC not amenable to surgery/RAI treatment and may be used as a bridge to these first-line therapies.

Metastatic Papillary Thyroid Carcinoma Arising in a Neglected Goiter: A Case Report

BACKGROUND: Periodical clinical surveillance for early thyroid cancer detection among patients with diffuse goiter is a common scenario managed in the primary care setting. However, clinical palpation alone is neither sensitive nor specific in detecting the presence of nodules within a goiter. Hence, further investigation with ultrasound is key to effective surveillance for early detection of thyroid cancer.&#x0D; CASE REPORT: We present a case of a stable diffuse goiter in a 51-year-old woman diagnosed 30 years ago who refused further imaging investigation. Based solely on clinical palpation, the presence of nodules within the goiter was missed. This resulted in transformation into papillary thyroid carcinoma with lung metastases. She presented with progressive hoarseness of voice and cough for 3 months. An ultrasound of the thyroid gland revealed a large heterogeneous nodule in the left lower pole with coarse calcification and internal vascularity. Further imaging with contrast-enhanced computed tomography of the neck and thorax revealed an enhancing nodule in the left thyroid lobe which extends inferiorly to the left retroclavicular region which compresses the trachea causing narrowing of its lumen at T1 and T2 vertebral levels. There were multiple lung nodules in both lungs suggestive of metastases.&#x0D; CONCLUSION: A total thyroidectomy followed by radioactive iodine thyroid ablation therapy was performed. The histopathological examination revealed the surgical specimen to be papillary thyroid carcinoma.

Genomic landscape of metastatic papillary thyroid carcinoma and novel biomarkers for predicting distant metastasis.

Papillary thyroid carcinoma (PTC) is the most common malignancy of the thyroid gland, with a relatively high cure rate. Distant metastasis (DM) of PTC is uncommon, but when it occurs, it significantly decreases the survival of PTC patients. The molecular mechanisms of DM in PTC have not been systematically studied. We performed whole exome sequencing and GeneseeqPrime (425 genes) panel sequencing of the primary tumor, plasma and matched white blood cell samples from 20 PTC with DM and 46 PTC without DM. We identified somatic mutations, gene fusions and copy number alterations and analyzed their relationships with DM of PTC. BRAF‐V600E was identified in 73% of PTC, followed by RET fusions (14%) in a mutually exclusive manner (P < 0.0001). We found that gene fusions (RET, ALK or NTRK1) (P < 0.01) and chromosome 22q loss (P < 0.01) were independently associated with DM in both univariate and multivariate analyses. A nomogram model consisting of chromosome 22q loss, gene fusions and three clinical variables was built for predicting DM in PTC (C‐index = 0.89). The plasma circulating tumor DNA (ctDNA) detection rate in PTC was only 38.9%; however, it was significantly associated with the metastatic status (P = 0.04), tumor size (P = 0.001) and invasiveness (P = 0.01). In conclusion, gene fusions and chromosome 22q loss were independently associated with DM in PTC and could serve as molecular biomarkers for predicting DM. The ctDNA detection rate was low in non–DM PTC but significantly higher in PTC with DM.

Apatinib Inhibits Cell Proliferation and Induces Autophagy in Human Papillary Thyroid Carcinoma via the PI3K/Akt/mTOR Signaling Pathway

Background: Patients with metastatic radioiodine-refractory papillary thyroid carcinoma (PTC) have limited treatment options and a poor prognosis. There is an urgent need to develop new drugs targeting PTC for clinical application. Apatinib, a novel small-molecule tyrosine kinase inhibitor (TKI), is highly selective for vascular endothelial growth factor receptor-2 (VEGFR2) and exhibits antitumor effects in a variety of solid tumors. Although apatinib has been shown to be safe and efficacious in radioiodine-refractory differentiated thyroid cancer, the mechanism underlying its antitumor effect is unclear. In this report, we explored the effects of apatinib on PTC in vitro and in vivo.Methods: VEGFR2 expression levels were evaluated by immunohistochemistry (IHC), qPCR, and western blotting (WB). The effects of apatinib on cell viability, colony formation, and migration in the Transwell assay were assessed in vitro, and its effect on tumor growth rate was assessed in vivo. In addition, the levels of proteins in signaling pathways were determined by WB. Finally, the autophagy level was assessed by WB, immunofluorescence (IF), and transmission electron microscopy.Results: We found that high VEGFR2 expression is associated with tumor size, T stage, and lymph node metastasis in patients with PTC and that apatinib inhibits PTC cell growth, promotes apoptosis, and induces cell cycle arrest through the PI3K/Akt/mTOR signaling pathway. Moreover, apatinib induces autophagy, and pharmacological inhibition of autophagy or small interfering RNA (siRNA)-mediated targeting of autophagy-associated gene 5 (ATG5) can further increase PTC cell apoptosis.Conclusion: Our data suggest that apatinib can induce apoptosis and autophagy via the PI3K/Akt/mTOR signaling pathway for the treatment of PTC and that autophagy is a potential novel target for future therapy in resistant PTC.

Hypermethylated RASSF1 and SLC5A8 promoters alongside BRAFV600E mutation as biomarkers for papillary thyroid carcinoma.

Circulating cell-free DNA (cfDNA) has been considered as a diagnostic source to track genetic and epigenetic alterations in cancer. We aimed to study mutation in addition to the methylation status in the promoter regions of RASSF1 and SLC5A8 genes in tissues and circulating free DNA samples of patients affected with papillary thyroid carcinoma (PTC) and thyroid nodules as controls. BRAFV600E mutation was studied by ARMS-scorpion real-time polymerase chain reaction method in 57 PTC and 45 thyroid nodule cases. Methylation status of RASSF1 and SLC5A8 promoter regions was analyzed by methylation-specific high-resolution melting curve analysis. BRAFV600E mutation was found in 39 (68.4%) out of 57 PTC tissue samples, while in 33 (49.1%) cases of cfDNA, this mutation was detected. The frequency of BRAFV600E mutation in cfDNA was significantly different between metastatic and nonmetastatic PTC cases (22 of 33 PTC cases vs. 5 of 34 thyroid nodule samples). Methylation levels of three promoter regions of SLC5A8 and proximal promoter region of RASSF1 was significantly different between PTC and thyroid nodule cases in both cfDNA and tissue DNA. In addition, the methylation status of these two genes in tissue DNA was reflected in methylation status observed in cfDNA. This study confirmed that BRAFV600E mutation is better for discrimination between papillary thyroid carcinoma and thyroid nodules. On the other hand, hypermethylation in the more proximal promoter regions to RASSF1 and SLC5A8 genes showed higher sensitivity and more acceptable specificity for this discrimination.

Diagnostic imaging in the preoperative airway assessment: cervical spine destabilization from metastatic papillary thyroid carcinoma

Diagnostic imaging in the preoperative airway assessment: cervical spine destabilization from metastatic papillary thyroid carcinoma

A histopathological surprise of retroperitoneal tumor

Metastatic papillary carcinoma of thyroid in euthyroid patient surprisingly presented as retroperitoneal mass. The rarity of the lesion, non specific symptoms ad signs made the pre operative diagnosis very difficult, but the histological report made the case very interesting. However because of the rarity of the presentation the diagnosis and management is not clearly defined and hence the associated patient outcome also. Till our knowledge through this paper we are presenting the first case of metastatic papillary carcinoma of thyroid which presented as retroperitoneal tumor.

Preparation and SPECT/CT Imaging of 177Lu-Labeled Peptide Nucleic Acid (PNA) Targeting CITED1: Therapeutic Evaluation in Tumor-Bearing Nude Mice.

PurposeThe expression of Cbp/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 1 (CITED1) is upregulated in papillary thyroid carcinoma (PTC) and mediates cell proliferation and migration. To facilitate early diagnosis and monitoring of recurrent or metastatic PTC, we designed 177Lu-labeled antisense peptide nucleic acid (PNA) targeting CITED1 mRNA to evaluate the therapeutic potential, while analyzing its distribution in nude mice and the characteristics withsingle-photon emission-computed tomography/computed tomography (SPECT/CT) imaging.Materials and Methods177Lu-DOTA-anti-CITED1-PNA (177Lu-asPNA) was obtained by indirect labeling. High-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC) were used to determine the labeling rate and radiochemical purity. The stability of 177Lu-asPNA was evaluated by TLC, and the radioactivity count was measured by a γ counter to calculate its uptake capacity in K1 cells. To analyze the distribution of 177Lu-asPNA in body tissues and organs of nude mice, static single-photon emission-computed tomography (SPECT) imaging and SPECT/CT image fusion were performed. Then, the therapeutic effects of probes were explored by tumor growth curves and survival analysis.ResultsOur probe showed a radiochemical purity of 96.5±0.15% at 1 hr and specific activity of 8.7±0.53 MBq/μg. The uptake rate in the 177Lu-asPNA group was much higher than that in the 177Lu-DOTA-nonsense-PNA (177Lu-nonsense-PNA) and 177Lu-DOTA groups (P<0.05). The biological distribution showed that the tumor/muscle ratio was at its highest at 24 h (4.98±0.34) post-inoculation, with SPECT/CT imaging showing clear tumor development. By measuring tumor volume of tumor-bearing nude mice, the 177Lu-asPNA group showed a significant difference in tumor size 9 days after injection (P < 0.05). Kaplan-Meier survival curves showed that the overall survival rate in the 177Lu-asPNA group was significantly different from those in the DOTA-anti-CITED1-PNA (asPNA) and saline groups (P = 0.002, log-rank test).Conclusion177Lu-asPNA was developed successfully, showing a high labeling rate and good stability. SPECT/CT imaging demonstrated tumor growth in nude mice, which was effectively inhibited by our probe, thus prolonging survival.

Anaplastic Transformation of Metastatic Papillary Thyroid Carcinoma in a Cervical Lymph Node: a Timeline and Short Review

Anaplastic Transformation of Metastatic Papillary Thyroid Carcinoma in a Cervical Lymph Node: a Timeline and Short Review

Complex management decisions in a woman with concurrent primary hyperparathyroidism and metastatic papillary thyroid carcinoma, both presenting during pregnancy.

SummaryA 40-year-old woman was hospitalised at 25-week gestation following a diagnosis of severe symptomatic hypercalcaemia (adjusted serum calcium 3.02 mmol/L). A diagnosis of primary hyperparathyroidism (PHP) was made on the basis of elevated parathyroid hormone (PTH) 11.2 pmol/L (reference range 1.5–6.9) and exclusion of familial hypocalciuric hypercalcaemia. Ultrasound examination of the neck did not convincingly demonstrate an abnormal or enlarged parathyroid gland and parathyroid scintigraphy was not performed due to maternal choice relating to perceived radiation risk to the foetus. At neck exploration during the 28th week of pregnancy a right lower pole parathyroid lesion was excised together with two abnormal lymph nodes (largest 1.6 cm). Histology confirmed a parathyroid adenoma and also papillary thyroid carcinoma deposits in the two resected lymph nodes. Post-operatively, levels of adjusted serum calcium normalised and pregnancy progressed uneventfully to term. Total thyroidectomy was performed 2 weeks after delivery revealing two small foci of papillary micro-carcinoma (largest 2.3 mm, one in each thyroid lobe) with no evidence of further metastatic tumour in lymph nodes removed during functional neck dissection. Radioiodine remnant ablation (RRA) was performed 2 months post thyroidectomy to allow for breast involution. The patient remains in full clinical and biochemical remission 9 years later. We present and review the difficult management decisions faced in relation to the investigation and treatment of PHP in pregnancy, further complicated by incidentally discovered locally metastatic pT1aN1aM0 papillary thyroid carcinoma.Learning points:PHP may have serious consequences during pregnancy and usually requires surgical management during pregnancy to reduce the risk of maternal and foetal complications. The indications for and optimal timing of surgical management are discussed.Localisation by parathyroid scintigraphy is controversial during pregnancy: modified dose regimes may be considered in preference as an alternative to unguided neck exploration.Breastfeeding is contraindicated for 6–8 weeks before radioactive-iodine remnant ablation (RRA) to prevent increased breast uptake. Breastfeeding is further contra-indicated until after a subsequent pregnancy.Incidentally discovered differentiated thyroid carcinoma (DTC) in cervical lymph nodes in some cases may be managed expectantly because in one quarter of thyroidectomies the primary tumour remains occult.

Fracture of the Humeral Bone as the First Clinical Presentation of Metastatic Papillary Thyroid Carcinoma in Ibadan

Papillary thyroid carcinoma is the commonest type of thyroid cancer representing 75 to 85 per cent of all thyroid cancer cases. It is often well-differentiated, slow-growing, and localized, although it can metastasize. This is a case of a 49-year-old male who presented with a pathological fracture of the left humerus. A bone biopsy was done at the surgery which had a histological diagnosis of metastatic thyroid carcinoma. A total thyroidectomy was subsequently done and was histologically reported as a follicular variant of papillary thyroid carcinoma. The patient was clinically stable post-thyroidectomy and was discharged home on the 10th postoperative day and he is currently being followed-up in the surgical outpatient clinic. Pathological fracture as the initial clinical presentation is an unusual manifestation of metastatic thyroid carcinoma; therefore a high index of suspicion is needed to make this diagnosis. In any patient presenting with a pathologic fracture, the possibility of metastatic carcinoma from the thyroid gland should always be considered.

517P - Immunohistochemical expression of ER-α and PR in papillary thyroid carcinoma

BackgroundPapillary thyroid carcinoma (PTC) is the most common thyroid cancer with multiple risk factors including exposure to ionizing radiation. Estrogens contribute to papillary carcinoma development by promoting cell proliferation and invasion of mutated epithelial follicular cells. The present study aimed to assess ER-α and PR expression in PTC and to correlate their expression with the clinicopathological parameters in this cancer. MethodsThis study included 62 primary and six metastatic papillary thyroid carcinoma cases. ResultsNineteen and 38.7% of primary PTC cases showed positive nuclear expression for ER and PR, respectively. Metastatic cases showed 66.7% positive ER expression and all were negative for PR. Estrogen receptor expression showed significant higher positivity in metastatic compared to primary PTC (p=0.02) and it was significantly associated with primary PTC associated with thyroiditis (p = .002). Progesterone receptor expression was significantly associated with old age in primary PTC (p = .003) and it showed significant coparallel expression with ER (p = .000). ConclusionsEstrogen and progesterone receptors expressed in papillary thyroid carcinoma opening the door for further studies to verify if those patients could benefit from hormonal therapy. Estrogen receptor seems to have a role in metastatic process of PTC as malignant cells express it in metastatic more than primary site. The presence of lymphocytes in the stroma may promote ER expression in adjacent PTC, necessitating further studies on PTC cases associated with Hashimoto thyroiditis to verify this assumed relationship. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

LUNG NODULE WITH PAPILLARY FEATURES ON BIOPSY: A DIAGNOSTIC DILEMMA

SESSION TITLE: Monday Medical Student/Resident Case Report Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/21/2019 02:30 PM - 03:15 PM INTRODUCTION: Papillary adenocarcinoma (PA) is a rare sub type of adenocarcinoma of the lung. It can have histological and immunohistochemistry features like papillary thyroid carcinoma (PTC). We report a case of lung nodule found to have features suggestive of PTC on biopsy. CASE PRESENTATION: A 69-year-old female with a history of COPD and colon cancer presented to the pulmonologist for follow up of a solitary lung nodule in the right upper lobe, which was first diagnosed two years back. It had shown a recent increase in size from 8 mm to 12 mm, with spiculated pattern on imaging. Biopsy of the lung nodule was highly suspicious for PTC, with positive TTF1, papillary features, intranuclear cytoplasmic inclusions, nuclear grooves, negative CK20, CDX2 immunostain. She denied any symptoms of hypo/hyperthyroidism, weight loss, fatigue, cough, dyspnea, neck radiation exposure. She had a 37.5 pack-year smoking history. Family history was non-contributory. Vital signs and physical examination were unremarkable. Thyroid function tests including TSH, fT3, fT4 were within normal limits. With findings suggestive of PTC on biopsy, initial concern was for metastatic disease. Thyroid ultrasound showed 0.7cm cystic nodule in the right lobe, and two solid nodules of 0.9cm, 0.8cm on the left. FNAC of the nodules showed benign pathology. Tumour board was consulted, and they recommended MRI of the neck with contrast which revealed mildly enlarged thyroid with sub centimetric nodules, without lymphadenopathy, making our suspicion for metastatic PTC very low. Ectopic thyroid tissue carcinoma, PA of the lung were now being considered as differentials. Lung biopsy slides were sent to Mayo clinic for a second opinion, which revealed neoplastic cells with lining of papillary structures, with positive immunochemistry for napsin-A and TTF1, and negative for Pax-8, confirming the diagnosis of primary PA. DISCUSSION: PA accounts for 7-12% of lung adenocarcinomas, with a predilection for female smokers. It mimics PTC, as they can have similar histological features of pseudo-inclusions, intra-nuclear grooves. In such cases, immunohistochemistry aids in the diagnosis. Although, our patient had a nodule which morphologically resembled PTC, the history of solitary lung nodule, in the absence of significant findings on imaging and biopsy made the diagnosis of PTC unlikely. CONCLUSIONS: Most common etiology for lung nodule showing papillary features is metastatic disease. The combination of positive TTF1, napsin-A, and negative Pax-8 is a reliable tool to differentiate primary lung adenocarcinoma from metastatic tumors. Understanding the existence of papillary thyroid carcinoma-like primary pulmonary papillary adenocarcinoma will avoid misdiagnosis or unnecessary investigations. Reference #1: Zhu YZ, Li WP, Wang ZY, Yang HF, He QL, Zhu HG, Zheng GJ. Primary pulmonary adenocarcinoma mimicking papillary thyroid carcinoma. J Cardiothoracic Surg. 2013; 17; 8:131 Reference #2: El-Maqsoud NM, Tawfiek ER, Abdelmeged A, Rahman MF, Moustafa AA. The diagnostic utility of the triple markers Napsin A, TTF-1, and PAX8 in differentiating between primary and metastatic lung carcinomas. Tumour Biol. 2016; 37(3):3123-34 Reference #3: Karmakar S, Nath A, Neyaz Z, Agarwal V, Ahsan S. Primary papillary adenocarcinoma of lung: Report of two cases. Lung India. 2017; 34(3):299-302 DISCLOSURES: No relevant relationships by Shujaa Faryad, source=Web Response No relevant relationships by Pallavi Pradeep, source=Web Response

Incidental Mediastinal Thyroid Cancer

Cystic mediastinal masses are most commonly benign congenital lesions. Rarely, a cystic mediastinal mass will prove to be malignant. The patient, a 50-year-old woman who initially presented with uveitis, was incidentally found to have a right paratracheal opacity on chest X-ray (CXR). Chest computed tomography (CT) demonstrated a 5cm right paratracheal hypodense cystic mass. The patient underwent a right robotic-assisted thoracoscopic resection of the mediastinal mass. Final pathology revealed a 4.5cm mass consistent with metastatic papillary thyroid carcinoma (similar histology in 2 excised lymph nodes). The patient subsequently had a total thyroidectomy with central and right neck dissections.

Intramedullary Spinal Cord Metastasis as the Presenting Feature of Papillary Thyroid Carcinoma

The objective of this report is to present an unusual case of intramedullary spinal cord metastasis (ISCM) as the presenting feature of papillary thyroid carcinoma (PTC). The presented case includes clinical, biochemical, and imaging findings as well as surgical and pathology reports. Treatment with radioactive iodine (RAI) and the response to this treatment are presented. A 71-year-old woman was evaluated for debilitating low back pain and walking disability. Magnetic resonance imaging demonstrated an oval, lumbar, intramedullary mass with benign features and surgery was scheduled. On preoperative evaluation for the lumbar mass, a multinodular thyroid goiter (unfortunately overlooked previously) was noticed, causing severe narrowing of the trachea. Total thyroidectomy was performed with a pathology diagnosis of PTC. In a second operation, the lumbar lesion was removed and proved to represent metastatic PTC. External beam radiation was subsequently administered to the thyroid bed, lumbar spine, and other skeletal metastases, followed by 150 milliCurie of RAI. A post-treatment scan showed high uptake over the lumbar spine, and skeletal and lung lesions. Clinically, the patient restored her walking ability and back pain improved. ISCM rarely is the presenting feature of PTC. Our patient presented with back pain which is the typical, though non-specific symptom, of ISCM. She showed good clinical response to multimodal treatment which is in line with the few other differentiated thyroid cancer patients with ISCM reported in the literature. Prompt surgical resection, followed by external beam radiation and RAI, may improve neurological signs, alleviate pain, and improve quality of life.