Hypoechoic Solid Nodule Research Articles

6925 A Rare Case of Metastatic Papillary Thyroid Carcinoma Confined to Cervical Lymph Node with No Identifiable Primary Tumor In The Thyroid Gland. A Diagnostic Conundrum

Abstract Disclosure: R. Abdelmasih: None. W. Pan: None. Introduction: Papillary thyroid carcinoma (PTC) is the most common treatable thyroid cancer (TC) with very good prognosis. Metastatic PTC either in the lymph node LN or extra-nodal with no primary thyroid lesion identified is a rare phenomenon referred to as occult thyroid carcinoma (OTC). Despite its rarity, it is reported and constitute a diagnostic conundrum. herein we present a case of metastatic PTC identified in cervical lymph nodes (LN) without a primary tumor in the thyroid gland confirmed with surgical pathology. Case Presentation: A 43-year-old female with history of post-ablative hypothyroidism after treatment of toxic nodular goiter for 10 years, with no family history of thyroid cancer presented with incidentally found left 1.8 Heterogeneous hypoechoic solid nodule with lobulated borders and internal calcifications along with left-sided 0.8 LN without normal fatty hilum on Ultrasound Head and Neck. Fine needle aspiration of the left thyroid nodule and suspicious LN revealed PTC in the left LN though the thyroid nodule sample was non-diagnostic. CT of head and neck showed partially calcified thyroid nodule, Hyperattenuating 8 mm left III LN without fatty hilum, and 9 mm left II calcified LN. Patient underwent total thyroidectomy, central neck, and left lateral neck dissection. Surgical pathology showed no malignancy in thyroid gland or central LNs and 1 out 5 LN of the left neck dissection showed PTC with tumor grading of pT0 pN1b pMNA. patient underwent whole-body thyrogen-stimulated thyroid scan which showed iodine avid tissue in the thyroid bed followed by high-dose I-131 radioactive iodine ablation (RAI). Discussion: OTC refers to impalpable incidental TC less than 10 mm per the WHO. Boucek et al classify OTC into four categories, recently a fifth category was added, in which metastasis is confirmed either in regional LN or distant metastasis though thyroid tissue is confirmed to be benign per pathology and imaging evaluation, our patient falls in the fifth category. Hypothesis of this phenomenon is not well understood, one suggested explanation is missed diagnosis due to not enough sample or if lesion is less than 3 mm. another hypothesis is tumor spontaneous regression, or regression secondary to treatment that was inadequate to treat the systemic process of the tumor, which we believe our patient fits in this hypothesis, given that she underwent RAI ablation many years ago. Tumor regression is very rare and reported to be 1 in 140,000 cases. Another theory suggests that PTC can arise in ectopic thyroid tissue. This case is to shed light on a rare clinical and pathological entity to avoid missed diagnoses. Prognosis depends on the extent of metastasis, with favorable one when it is limited to regional LN and worse with distant metastasis. More cases reports are warranted to help guide further management of such cases due to the lack of available guidance in use of RAI surveillance and ablation. Presentation: 6/1/2024

Ultrasonographic features and diagnostic accuracy of FNA and CNB in secondary thyroid malignancies: A retrospective study

ObjectiveThis study aims to examine the ultrasonographic features of secondary thyroid malignancies and compare the diagnostic efficacy of fine-needle aspiration (FNA) and core needle biopsy (CNB) in this condition. MethodsA retrospective analysis was conducted on 29 patients with secondary thyroid malignancies treated at our center between July 2011 and October 2022. Ultrasound images and clinical data were analyzed, and the lesions were classified according to the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS). ResultsAmong the 29 patients studied, primary tumor sites were predominantly the esophagus, lung, and nasopharynx. Comprehensive ultrasound data was available for 28 of these patients, revealing nodular lesions in 24 cases and diffuse lesions in 4 cases. Nodular lesions were predominantly solid or nearly solid hypoechoic nodules with parallel growth and extrathyroidal extension features, with a few showing macrocalcifications. Most patients had varying degrees of metastasis to neck lymph nodes. FNA accurately diagnosed 31.6 % of the lesions as secondary thyroid malignancies, while 5.3 % were misdiagnosed as papillary thyroid carcinoma (PTC). However, CNB demonstrated 100 % reliability in diagnosing secondary thyroid malignancies. ConclusionThis study's categorization of secondary thyroid malignancy ultrasonographic features identifies nodular and diffuse patterns, with the application of ACR TI-RADS proving effective for nodular types. In detecting these lesions, CNB demonstrates superior sensitivity compared to FNA. Thus, in cases of thyroid lesions suspected to be malignant, particularly with enlarged neck lymph nodes and in patients with a history of malignancy, CNB is recommended as the diagnostic method of choice.

Sonographic characteristics of diffuse sclerosing variant of papillary thyroid carcinoma with histopathological correlation: a preliminary study

BackgroundDiffuse sclerosing variant of papillary thyroid carcinoma (DSVPTC) is a rare but high invasive subtype of papillary thyroid carcinoma, which mandates an aggressive clinical strategy. Few studies have focused on the sonographic characteristics of DSVPTC and the role of ultrasound in diagnosis and treatment of this variant remains unknown. This study aimed to identify and understand DSVPTC more accurately under ultrasound in correlation with pathology.MethodsThe ultrasound characteristics and histopathologic sections of 10 lesions in 10 DSVPTC patients who underwent thyroid surgery at our center between 2014 and 2020 were reviewed and compared with 184 lesions in 168 classic variant of papillary thyroid carcinoma (cPTC) patients.Results6 DSVPTC cases (60%) showed the “snowstorm” pattern on sonogram and 4 cases (40%) presented hypoechoic solid nodules only. Vague borders (100.0% vs. 18.5%, P = 0.019) and abundant microcalcifications (66.7% vs. 10.9%, P = 0.037) were more common in DSVPTC nodules than in cPTC nodules, corresponding to the infiltrating boundaries and numerous psammoma bodies under the microscope respectively. Most of the DSVPTC cases had a heterogeneous background (80%) and suspicious metastatic cervical lymph nodes (80%) on sonograms. All DSVPTC cases had histopathological metastatic cervical lymph nodes.ConclusionThe sonographic “snowstorm” pattern indicated DSVPTC with whole-lobe occupation. Hypoechoic solid nodules with vague borders and abundant microcalcifications on sonogram suggested DSVPTC lesion with an ongoing invasion. Regardless of which of the two sonograms was shown, the corresponding DSVPTC lesions were aggressive and required the same attention from the surgeons.

Parathyroid carcinoma: Imaging features of initial presentation and recurrence. A single center experience.

Parathyroid carcinoma is the rarest endocrine neoplasm with very few published data discussing its imaging appearance with primary focus on ultrasound imaging features. We present our 23 years institutional experience to highlight multimodality imaging evaluation at presentation and at recurrence. Retrospective chart review of clinical and pathological diagnosis of parathyroid carcinoma patients presented for initial or recurrent disease management at M.D. Anderson Cancer Center between the period of January 2000 and February 2023 was performed. Imaging findings on US, CT, PET/CT, and technetium-99m sestamibi were analyzed for initial and local recurrent parathyroid carcinoma. We further assess patterns of distant recurrence and its location. Twenty three patients with pathological and clinical diagnosis of initial (14 patients) or recurrent parathyroid carcinoma (14 patients) were included in this study. US findings of parathyroid carcinoma were larger lesions, increased/irregular vascularity, and non-circumscribed margins. Multiphasic CT findings of parathyroid carcinoma included an arterially enhancing lesion that is hypoenhancing relative to the thyroid and demonstrates no washout on delayed imaging. Highly suggestive findings for recurrent disease included a hypoechoic solid nodule (91.67%) with increased vascularity on ultrasound (81.8%) with corresponding enhancement on CT. Parathyroid carcinoma is a rare malignancy often diagnosed after surgical resection. We provided CT and US imaging features that are helpful in suggesting the diagnosis of parathyroid carcinoma and detection of early local recurrence.

FRI368 Thyroid Paraganglioma: A Rare Manifestation Of Paraganglioma Syndrome Associated With SDHD Mutation

Abstract Disclosure: K. Samuel: None. C. McMullen: None. C. Veloski: None. S. Kushchayev: None. J.E. Hallanger-Johnson: None. J. Hernandez Prera: None. J. Muzaffar: None. G.Q. Yang: None. V. Tarasova: None. Background: Thyroid paragangliomas (TP) are exceptionally rare, representing 0.5% of all paragangliomas (PGL) with total of less than 70 cases reported to date. We report a case of a TP presenting with an indeterminate thyroid nodule, as a first manifestation of multifocal head and neck PGL, associated with succinate dehydrogenase complex subunit D (SDHD) mutation. Clinical case: A 59-year female was initially seen at the tertiary referral center for an indeterminate thyroid nodule discovered incidentally on neck ultrasound (US) ordered for evaluation of a palpable posterior left neck mass. Neck/thyroid US showed multiple nonspecific bilateral lymph nodes measuring up to 1.2 cm and a 1.7 cm right interpolar markedly hypoechoic and hypervascular solid thyroid nodule (TR5). Clinically, the patient did not have symptoms related to the thyroid nodules or lymph nodes in the neck. Thyroid function tests were within normal range. An US-guided FNA biopsy was nondiagnostic. Core biopsy was suspicious for papillary thyroid carcinoma (hypercellular thyroid parenchyma with some follicular cells with nuclear irregularity, grooves, and hyperchromasia). Pathology slides review at the tertiary center showed nondiagnostic sample (Bethesda I) on cytopathology and neuroendocrine neoplasm consistent with PGL on core biopsy (immunohistochemical stains showed tumor cells positive for synaptophysin, chromogranin and GATA3. TTF1, TG, calcitonin, CEA and AE1/3 negative). US of the neck/thyroid 4 months later showed stable disease. Calcitonin and 24-h urinary catecholamines, metanephrines were within normal limits. There was no family history of pheochromocytoma or PGL. Genetic testing showed germline SDHD mutation (p.P81L(c.242c>5). 68Ga-DOTATATE PET/CT revealed multifocal areas of increased somatostatin receptor expression from the skull base to the left thoracic inlet, which included right and left skull base lesions, left neck level IIA lymph node, right and left level III lymph nodes, right thyroid lobe lesion, and left prevascular superior mediastinal lesion. An MRI of the brain and neck with and without contrast showed 1.7 cm right jugular, 0.6 cm right carotid, and 0.6 cm left vagal PGL, 1.3 cm right thyroid nodule, left level II 1.1x.6 cm lymphadenopathy, and 0.4 cm left superior mediastinal nodule. A CT of the neck w/contrast showed multiple areas likely representing bilateral carotid body tumors, left vagal PGL, right glomus jugular, and thyroid PGL stable over 6 months. MIBG nuclear medicine scan revealed no radiotracer accumulation in the lesions. EBRT therapy is planned to the skull base lesion. Conclusions: TP should be considered in the differential diagnosis of hypervascular thyroid nodules in patients with SDH-related pheochromocytoma-PGL syndromes. This case illustrates the importance of experienced multidisciplinary team evaluation and management of complex and rare PRG cases. Presentation: Friday, June 16, 2023

FRI691 Intrathyroidal Parathyroid Adenoma With Congenitally Absent Contralateral Thyroid Lobe Treated With Thermal Ablation

Abstract Disclosure: L. Bilandzic: None. L. Bilandzic: None. H. Korkusuz: None. We present a rare case of primary hyperthyroidism with ectopic adenoma located in the right thyroid lobe with congenitally absent left thyroid lobe which was treated with thermal ablation. A 60-year-old woman was referred to endocrinology clinic for further evaluation of her elevated total serum calcium of 11.4 mg/dL (reference range 8.5-10.5), elevated parathyroid hormone (PTH) level of 106 (10-60 pg/mL). Bone mineral densitometry showed a total T score of -2.9 in L1-L4. Other results were vitamin D 25-OH 30 ng/mL (ref. range 30 - 100), TSH 3.36 µIU/mL (ref range 0.4-5.0), eGFR 83 (normal > 59 mL/min/ 1.73 m²). She was asymptomatic and had no history of kidney stones. Other causes of hypercalcemia were refuted. Given the osteoporosis in her lumbar spine, parathyroid localization and surgery were suggested. Thyroid and parathyroid sonography demonstrated a solid hypoechoic nodule in the right thyroid lobe, 12x10x11mm, with smooth margins, no calcifications, classified as ACR TI-RADS T4. Left thyroid lobe was not appreciated and was considered to be congenitally absent since the patient did not have a history of a previous thyroid resection. Further localization studies (99mTc Sestamibi parathyroid scintigraphy and 4D-CT of the neck) did not reveal any other possible candidates for parathyroid adenomas. Eventually, a fine needle aspiration of the nodule in the right thyroid lobe was performed. PTH needle wash showed a PTH value of 633 pg/mL whereas the PTH value ≥ 100 pg/mL is suggestive of the presence of PTH secreting tissue. Given the thyroid anatomy found with this patient, a right lobe hemithyroidectomy would result with a permanent substitution dependent hypothyroidism. As an alternative, thermal ablation was presented as a treatment option for which the patient opted. She underwent the procedure in local anesthesia. Sonographic imaging of the adenoma was followed by the percutaneous insertion of the coagulation electrode. The utilized high frequency ablator was used with an output of 9 to 40 W and a frequency of 470 ± 10 kHz. There were no complications developed during or after the procedure. Two weeks after the thermal ablation, PTH level was measured at 55 pg/mL, total serum calcium at 9.5 mg/dL, TSH 1.01 µIU/mL. Sonography showed a hyperechoic nodule at the former location of the parathyroid adenoma, which was evaluated as a scar tissue. Three months after the procedure total calcium was at 9.3 mg/dL, PTH at 58 pg/mL, hence no biochemical evidence of pHPT. This is a rare case of ectopic parathyroid adenoma located in the thyroid gland with hemi agenesis of the contralateral lobe. A minimally invasive thermal ablation was performed with the goal of inactivation of the adenoma and preserving the euthyroid function. Presentation: Friday, June 16, 2023

SAT198 Parathyroid Adenoma Masquerading As A Thyroid Nodule

Abstract Disclosure: A. Arida: None. M. Papaleontiou: None. N. Esfandiari: None. Background: The diagnosis of parathyroid adenomas using a neck ultrasound (US) can be challenging when not performed by an experienced radiologist. Additional methods of diagnosis have been implemented to distinguish the differential diagnosis of a nodule in the neck. Clinical Case: A 48-year-old woman with a history of type 2 diabetes, hypercalcemia, and kidney stones presented for evaluation of a lump in the neck of 5 years duration. Prior thyroid US showed a solid hypoechoic nodule superior to the left thyroid lobe measuring 2.2 x 1.2 x 1.1 cm with hypervascularity. Her first FNA biopsy of this nodule reported benign cytology 5 years ago. A parathyroid scintigraphy scan was negative. Repeat FNA biopsy of this nodule showed follicular lesion of undetermined significance (Bethesda category III). Surgical consultation was recommended but she decided to seek a second opinion. A repeat neck US identified a solid vascular 1.6 cm nodule along the anterior margin of the superior left thyroid lobe. Some vascularity was extending from the thyroid tissue into the nodule. It was noted that this may represent an extrathyroidal nodule or arise from the thyroid gland with a score of TIRADS 4. Laboratory tests confirmed primary hyperparathyroidism with an iPTH of 126 pg/mL (normal range, 10-65 pg/mL) and serum calcium of 10.9 mg/dL (normal range, 8.6-10.3 mg/dL). After normalizing vitamin D levels, these values remained elevated. A repeat FNA biopsy of this nodule showed evidence of intrathyroidal parathyroid tissue. Immunostains were performed on the cell block material from the FNA biopsy. Scattered groups of cells were positive for PTH while being negative for TTF-1. Further needle washout for iPTH measurement revealed an iPTH >2000 pg/mL confirming the diagnosis of a parathyroid adenoma. Parathyroid surgery was recommended as per guidelines. Discussion: Once primary hyperparathyroidism is confirmed, the localization of parathyroid adenoma is pursued by a neck US and/or parathyroid scintigraphy. Parathyroid glands are located in the superior poles and in the inferior poles of the thyroid gland but ectopic locations like retropharyngeal, intrathyroidal, and mediastinal are possible. Typical US appearance is oval, solid, well-circumscribed, homogenous, and hypoechoic compared to the thyroid tissue. The color Doppler shows that the blood supply enters at the center and distributes peripherally presenting a “vascular arch” pattern that helps differentiate them from other lesions such as tumors or lymph nodes where the distribution is more centralized. Further needle washout for PTH level can confirm the diagnosis of parathyroid adenoma. Once a parathyroid adenoma is confirmed, minimally invasive parathyroid surgery can be recommended if surgery is indicated. Conclusion: A needle washout for measuring PTH in an FNA biopsy sample should be recommended when it is unclear whether a nodule is a thyroid nodule or a parathyroid adenoma. Presentation: Saturday, June 17, 2023

History of Thyroid Ultrasound.

From low-resolution images in the 1960s to current high-resolution technology, ultrasound has proven to be the initial imaging modality of choice for thyroid application. Point-of-care ultrasound has brought the technology to the thyroid specialist. Combined with physical examination, it provides real-time information regarding goiter, thyroid nodules, and thyroid cancer. Ultrasound-guided fine-needle aspiration biopsy has become the accepted norm, with biopsies rarely performed using palpation alone. Advantages of ultrasound-guided biopsy include precise placement of the needle within the nodule, selective sampling of areas with suspicious features, and accurate direction of the biopsy needle to actively growing viable cells in the periphery of the nodule. Education of endocrinologists in thyroid ultrasound began in the late 1990s and by 2016 more than 6000 clinicians had completed an ultrasound course. Concurrent with this rapid expansion of use of thyroid ultrasound was a rise in the diagnosis of small papillary carcinomas, which might have otherwise remained indolent and undetected. The 2009 American Thyroid Association Guidelines for the Management of Thyroid Nodules and Thyroid Cancer recommended biopsy for all solid hypoechoic nodules measuring larger than 1 cm. Attempting to decrease the frequency of biopsies of low-risk nodules, subsequent guidelines have focused on identifying and selectively biopsying those thyroid nodules at higher risk of clinically significant carcinoma based on ultrasound appearance. A major role for thyroid ultrasound has been in both preoperative staging and mapping to help determine the extent of surgery, as well as postoperative monitoring for locoregional soft tissue or lymph node metastases. With the recognition that the increase in papillary carcinoma was predominantly a result of early diagnosis of small often indolent cancers, active surveillance has become a promising management strategy for papillary thyroid microcarcinomas. Thyroid ultrasound is essential to active surveillance of thyroid cancer. Easy access to high-quality ultrasound studies is a requirement for a successful active surveillance program. Thyroid ultrasound has been used to facilitate interventional procedures, including treatment of thyroid nodules, treatment of recurrent thyroid cancer, and therapy of papillary thyroid microcarcinoma.

Abstract #1408165: An Atypical Case of Subacute Thyroiditis Presenting as a Toxic Adenoma

Subacute thyroiditis is inflammation of the thyroid gland often occurring after a viral infection of the upper respiratory tract. It is an uncommon condition mostly seen in women compared to men and is characterized by neck pain, a tender thyroid on exam with hyperthyroidism on initial presentation and low uptake on radioiodine imaging. A 36-year-old American Indian female with no significant past medical history was referred to Endocrinology for a new diagnosis of hyperthyroidism and for fine needle aspiration of thyroid nodules. Four months prior the patient was experiencing intermittent palpitations along with right sided neck pain. A thyroid ultrasound ordered by her primary care provider showed multiple nodules, including a 1.9 cm heterogeneous nodule with eccentric calcifications in the left lower lobe (TI-RADS 4) and a 2.7 cm right hypoechoic solid nodule with ill-defined borders, taller than wide (TI-RADS 5). Her thyroid function tests revealed a TSH < 0.025 uIU/mL (nl 0.450-4.50 uIU/mL), FT4 2.64 ng/dL (nl 0.82-1.7 ng/dL), FT3 6.4 pg/mL (nl 2.0-4.4 pg/mL) and thyroglobulin antibody < 1.0 IU/ml. A radioactive iodine uptake and scan showed decreased 24-hour uptake with a single hyperfunctioning nodule in the left thyroid lobe. The patient was started on methimazole 10 mg daily which was titrated down to 5 mg daily with normalization of her thyroid function after 3 months of treatment. Repeat thyroid function at the time of her endocrine clinic visit 1 month later revealed hypothyroidism. We performed a bedside ultrasound which did not show any thyroid nodules and the biopsy was cancelled. These findings were supported by a formal thyroid ultrasound a few weeks later. Methimazole was stopped and thyroid function normalized. Further history revealed the patient was experiencing symptoms of an upper respiratory tract infection a few weeks prior to the start of the palpations and neck pain. Six months after initial presentation, thyroid function has remained normal off methimazole. This is a rare case of subacute thyroiditis with initial findings of a toxic adenoma. To our knowledge there is only one other reported case of this unusual presentation of subacute thyroiditis with focal radioiodine uptake and thyroid nodules that later resolved on repeat imaging. This case should raise awareness for other providers to consider subacute thyroiditis when evaluating patients presenting with hyperthyroidism and atypical imaging findings. The history and clinical presentation were key in making the clinical diagnosis.

ODP510 Pseudolymphoma of the Thyroid Gland in Association with Hashimoto's Thyroiditis: A Benign Lesion in Whitish Thyroid Gland

Abstract Background Pseudolymphoma or reactive lymphoid hyperplasia is a benign localized tumor-forming lymphoid hyperplasia found in various organs. Its occurrence in the thyroid gland is rare and could mimic malignant lesion. Here, we present a case of pseudolymphoma of the thyroid in a patient with Hashimoto's Thyroiditis. Case description A 24-year-old woman without underlying disease presented with incidentally found thyroid nodule. Ultrasound revealed mild thyroid enlargement with diffuse heterogeneous parenchymal echotexture. A 5×7×8.5-mm hypoechoic solid nodule with irregular margin was found in the left upper pole. No microcalcification was detected. Multiple subcentimeter lymph nodes at bilateral cervical group VI and left cervical group IV were also detected, measuring up to 5 mm in short axis. Fine-needle aspiration was performed and suggested malignancy (Bethesda class V). Laboratory testing showed euthyroid state with positive anti-thyroglobulin antibodies and anti-thyroid peroxidase antibodies. The blood test and ultrasound findings suggested the underlying of Hashimoto's thyroiditis. The patient underwent total thyroidectomy and lymph node dissection without postoperative complication. Gross examination of the thyroid showed multiple well-demarcated whitish nodular lesions, ranging from 2-10 mm, in the upper pole of both thyroid lobe and a well-circumscribed area of a 7-mm greyish nodule in left thyroid lobe. Microscopically, the whitish lesion in both lobe composed of hyperplastic lymphoid tissues with many follicular centers on the background of lymphocytic thyroiditis. The immunohistochemistry study revealed a polyclonal nature of the plasma cell infiltrates. No abnormal staining with AE1/AE3 or cyclin D1 was found. Pseudolymphoma was diagnosed based on these findings. Papillary thyroid microcarcinoma (6 mm) without capsular invasion was also diagnosed in the lesion of left mid lobe. The cervical lymph nodes showed metastatic papillary thyroid carcinoma (1.5 mm) in level III cervical lymph nodes. No perinodal extension was found. Postoperative course was unremarkable and the patient was in stable condition at 18 months after the operation. Conclusion Although primary thyroid lymphoma is often considered in patients with Hashimoto's thyroiditis. The possibility of pseudolymphoma characterized by the presence of well-demarcated pearly white nodules and polyclonal cell populations should also be considered. Presentation: No date and time listed

PSUN380 A Case of Sclerosing Epithelioid Fibrosarcoma With Metastases to the Thyroid

Abstract Background Sclerosing Epithelioid Fibrosarcoma (SEF) is a rare form of soft tissue sarcoma, often presenting in the soft tissues of the extremities. This tumor is characterized by slow growth, often with local recurrences and/or distant metastases. First described in 1995, subsequent case reports and case series have demonstrated that metastases are primarily to the lung, pleura and bone, but can occur anywhere. Treatment is primarily by wide excision and adjuvant chemotherapy or radiotherapy. However, treatment of this rare form of sarcoma is often unsatisfactory. Clinical case A 36-year-old female, had for 30 years presented with a slowly enlarging mass on the left axilla. She had no constitutional symptoms and had previously been in good health. She was first diagnosed with SEF when she presented with abdominal pain where workup showed elevated Lipase 8,098 U/L (73-393 U/L) and Amylase 976 U/L (25-115 U/L). CT scans showed an ill-defined hypodense focus in the body of the pancreas, with incidental findings of a mixed intensity ovoid lesion in the left erector spinae, and heterogeneously enhancing ovoid masses in the left axilla, left lateral chest wall, left lower lung lobe, and the liver. Biopsy of the left axillary mass showed a round cell sarcoma consistent with Sclerosing Epithelioid Fibrosarcoma. PET scan confirmed widespread metastases to the lungs, pancreas, abdominal wall, left thigh and scalp. She underwent wide excision of the masses in the left axilla, thigh, and scalp. Adjuvant chemotherapy with Doxorubicin and Ifosfamide was then initiated. 6 months after starting treatment, she reported a rapidly enlarging anterior neck mass. She denied tremors, palpitations, any change in weight, heat/cold intolerance, changes in bowel movement, fatigue or muscle weakness. On physical examination there was a 2×2 cm, firm, non-tender, palpable nodule on the right thyroid lobe. Thyroid function tests were as follows: TSH 0.52 uIU/mL (0.55-4.78 uIU/mL), FT4 1.27 ng/dL (0.89-1.76 ng/dL), FT3 2.84 pg/mL (2.30–4.20 pg/mL). On thyroid ultrasound there was a 2.6×1.8×2.4 cm, mixed hypoechoic, solid, lobulated nodule in the upper to middle third of the right thyroid lobe, and a 0.3×0.2×0.3 cm hypoechoic solid nodule in the lower third of the left thyroid lobe. FNAB showed hypercellular smears with atypical round to spindle-shaped cells arranged in singly and loose to crowded clusters. She underwent total thyroidectomy, and histopathologic examination was consistent with a multifocal metastatic Sclerosing Epithelioid Fibrosarcoma. She was subsequently started on Levothyroxine replacement. Conclusion This case, to our knowledge, is the first reported case of Sclerosing Epithelioid Fibrosarcoma (SEF) metastatic to the thyroid. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

ODP503 Non-Small Cell Lung Cancer Metastatic to the Thyroid Gland

Abstract Introduction Metastatic disease affecting the thyroid gland is an uncommon phenomenon, with the most common primary sites being kidney, breast, lung and gastrointestinal tract. Thyroid metastases frequently occur simultaneously with spread to other sites and are rarely symptomatic. Clinical case: 73-year-old female with remote history of stage IA (T1c, N0, M0) invasive lobular carcinoma of the right breast treated with lumpectomy, radiation and tamoxifen, previous tobacco use, remote exposure to radiation during Chernobyl nuclear accident, developed progressive dyspnea on exertion. She was found to have a large left-sided pleural effusion. Thoracentesis was performed, and the cytology revealed adenocarcinoma with features favoring lung primary. Further imaging showed a left lower lobe mass with central necrosis and left hilar adenopathy, multiple pleural masses, and a small solitary brain lesion. PET-CT also demonstrated, amongst other findings, an FDG avid left lower pole thyroid nodule. Thyroid ultrasound was obtained to further characterize the lesion, which demonstrated a 0.8×1.3×1.3 cm solid hypoechoic nodule in the left mid lobe, which was thought to be corresponding to the PET avid nodule. Two additional nodules, a mixed cystic and solid measuring 1.7×2.1×2.9 cm on the right lobe, and another left-sided solid isoechoic measuring 0.8×0.7×0.9 cm, were noted. Thyroid FNA of the 1.3 cm PET avid nodule revealed rare cells in clusters, with large pale nuclei and prominent nucleoli, some with intracytoplasmic vacuoles, morphologically similar to those seen in the prior pleural fluid. Thin prep was stained with antibody to thyroglobulin, and the malignant cells showed lack of staining, supporting the diagnosis of metastatic lung cancer. Thyroid function tests were normal. Given lack of compressive symptoms, patient was maintained on her primary oncologic treatment with carboplatin and pemetrexed, and stereotactic radiation for the brain metastasis. Repeat PET-CT, performed approximately 8 months after the initial scan, showed mildly decreased focal FDG activity in the thyroid lesion. Discussion In this scenario, a patient with primary lung malignancy was found to have an FDG avid thyroid nodule which on FNA proved to be a metastatic lesion. Per some studies, such lesions can be seen in 1.4%–3% of patients who undergo surgery for suspected malignancy in the thyroid gland. Management of metastatic thyroid cancers depends on multiple factors including the primary malignancy location and staging, patient comorbidities, compressive symptoms, etc. Surgical management may be of benefit in isolated lesions in the thyroid. Conclusion When evaluating thyroid nodules in patients with known history of malignancy, it is important to consider the differential of metastatic lesions and to perform a thorough evaluation including fine-needle aspiration for clinical elucidation and management. Presentation: No date and time listed

ODP450 A Case of Metastatic Medullary Thyroid Cancer Presenting with Pathologic Hip Fracture

Abstract Introduction Medullary thyroid cancer accounts for less than 5% of thyroid malignancies. Distant metastatic disease typically presents in lymph nodes, lung, liver and bone. We present a patient who initially presented with a pathologic hip fracture with bone biopsy revealing medullary thyroid carcinoma. Case Description A 44-year-old male with no past medical history presented to the emergency department for right hip pain following a mechanical fall. Imaging showed a right femoral neck pathologic fracture as well as lytic lesions within the right femoral neck and right ilium. Family history was significant for pancreatic cancer and breast cancer. The patient underwent bone biopsy of the right femur followed by total hip arthroplasty. Bone biopsy revealed metastatic medullary thyroid carcinoma. Thyroid ultrasound showed a 1.2 centimeter right solid hypoechoic nodule along with extensive cervical lymphadenopathy. Further imaging revealed metastatic disease throughout the thoracic spine, mediastinal lymphadenopathy, and a left 2.2 centimeter adrenal lesion with peripheral enhancement and possible necrosis. Carcinoembryonic antigen (CEA) level was 551 ng/mL (normal &amp;lt;4.7), calcitonin was 2,498 pg/mL (normal &amp;lt;10), and calcium levels were normal. Plasma free metanephrines were normal and plasma normetanephrines were less than two times the upper limit of normal. Genetic testing on the bone biopsy specimen revealed a RET p. C618S variant. Germline RET testing was collected. The patient was discharged with close follow-up with oncology to initiate systemic therapy and follow-up with endocrinology for the adrenal mass. Discussion Majority of cases of medullary thyroid carcinoma are sporadic. Patients typically present with a thyroid nodule with many having cervical lymph node involvement at diagnosis and 5-10% having distant metastatic disease. Our patient's initial presentation was unique in that he presented with a pathologic fracture. Bone metastases can be seen in about 30% of cases of metastatic medullary thyroid carcinoma. Calcitonin levels greater than 500 pg/mL require additional imaging to exclude metastatic disease. If RET mutational status is unknown, patients should be screened for primary hyperparathyroidism and pheochromocytoma. Screening for pheochromocytoma is critical in preoperative management of these patients. Treatment for patients with metastatic disease involves surgery, external beam radiotherapy, and kinase inhibitors. Presentation: No date and time listed

PSAT283 Sclerosing Mucoepidermoid Cancer – A Unique Entity

Abstract Introduction - Sclerosing mucoepidermoid thyroid cancer is a rare entity with approximately 60 cases reported in the literature. Initially described by Chan. Et al in 1991,1 it was included as a separate entity by WHO in 2004.2 Previously considered to have indolent nature, recent evidence has reported aggressive nature ranging from local invasion to metastasis. Case - 66-year-old female with complaints of difficulty in swallowing, breathing, and sensation of a lump in her throat for last 6 months, was noted to have left thyroid mass on ultrasound. Thyroid ultrasound showed solid hypoechoic nodule, 8.2×5.3×5.9 cm replacing left thyroid lobe with solid hypoechoic nodule 2.2×1.1x 1.6 cm at the right end of the isthmus. The neck ultrasound was negative for lymph nodes. Past medical history was significant for long-standing hypothyroidism, and recently diagnosed invasive ductal carcinoma of the breast. CT chest showed an enlarged thyroid gland with substernal extension and mass effect on the trachea. FNA thyroid showed Bethesda category 5, suspicious for papillary thyroid cancer. The patient underwent a total thyroidectomy. Pathology for left nodule showed sclerosing mucoepidermoid carcinoma with eosinophils, 8.6×6.9×5.8 cm, p T4a N×Mx, with positive margins for tumor, no angiolymphatic invasion with co-existing right-sided papillary microcarcinoma (follicular variant) with chronic lymphocytic thyroiditis. Levothyroxine was dosed to aim goal TSH &amp;lt;0.1, considering the high risk of recurrence. Post-op Thyroglobulin was 1 ng/ml (&amp;lt; 2 ng/ml) with elevated Thyroglobulin antibodies 6.4 U/ml (&amp;lt;0.4). The patient further had radioiodine ablation with 150 mCi I-131, 3 months later. Post therapy whole-body scan showed multiple foci of increased uptake in thyroid bed consistent with thyroid tissue/ residual disease. No distant metastasis was noted. Discussion – Sclerosing mucoepidermoid cancer is thought to be derived from the ultimobranchial body.1 It is more common in females in age groups 3rd - 8th decade.3 Most common presentation is unilateral painless thyroid mass. Coexistent chronic lymphocytic thyroiditis and papillary thyroid cancer are usually found. On literature review of 56 cases, the gross extrathyroidal extension was seen in 26% of cases with distant metastasis was most commonly seen in lungs.3 No established treatment strategy exists due to a small number of reported cases, however, treatment ranges from only Thyroid surgery to Thyroid surgery with radiation +/- chemotherapy and radioactive iodine. References Shah AA, La Fortune K et al. Thyroid sclerosing mucoepidermoid carcinoma with eosinophilia: a clinicopathologic and molecular analysis of a distinct entity. Mod Pathol. 2017;30: 329–339. Pantola C, Kala S, Athar M, et al. Sclerosing mucoepidermoid carcinoma with eosinophilia of the thyroid: a cytological dilemma. J Cytol 2016; 33: 37. Chambers M, Nosé V et al. Salivary-Like Tumors of the Thyroid: A Comprehensive Review of Three Rare Carcinomas. Head Neck Pathol. 2021 Mar;15(1): 212-224. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

7572 Bladder Endometriosis: Robotic Surgery with 2 Low Accessory Ports - Two Case Reports

<h3>Study Objective</h3> To show the diagnosis and safe robotic surgical approach of two cases of vesical endometriosis using only 2 low accessory ports <h3>Design</h3> A presentation of the surgical approach of two clinical cases, with narrated video footage. <h3>Setting</h3> Patient is placed in the semi-gynecological position. Robotic side docking set for left lateral pelvic using da Vinci Si platform. <h3>Patients or Participants</h3> The first case is a 37-year-old patient, nulligest, complaining of increased urinary frequency and urinary urgency with worsening of the menstrual period, who presented, on physical examination, a palpable 2cm nodule in the anterior vaginal wall. Nuclear magnetic resonance (MRI) confirmed a solid nodule in the midline of the posterior wall of the bladder, measuring 2 × 1.5 × 1.8 cm. The second case is a 37-year-old woman, nulligest, complaining of dysmenorrhea, chronic pelvic pain and infertility, refractory to clinical and surgical treatment for endometriosis. The MRI showed a solid hypoechoic nodule on the left posterior wall of the bladder dome, infiltrating the detrusor muscle, measuring 2.5 × 2.1 cm, without involvement of the bladder trigone. <h3>Interventions</h3> Two partial cystectomies performed entirely by robotic surgery for the treatment of vesical endometriosis using only two accessory punctures of 8mm with good surgical performance, less invasive and with better aesthetic results for the patient. In addition, urethral extraction can be a possibility to optimize surgical time and avoid widening the incisions. <h3>Measurements and Main Results</h3> The patients were discharged early, showing good clinical evolution, with excellent aesthetic results. <h3>Conclusion</h3> We can conclude that robotic surgery for bladder endometriosis with only two low accessory punctures is possible, being less invasive and aesthetically better for the patient. In addition, minimal resection of the bladder tissue must be sought and the trigone preserved to avoid damage to the nerves.

An attempt to reduce unnecessary surgical procedures... Can ultrasound characteristics help in differentiating adenoma vs carcinoma in follicular thyroid neoplasms?

Introduction and objectivesThyroid nodules frequently require ultrasound and Fine Needle Aspiration Cytology (FNAC) evaluation. However, FNA cytology does not allow differentiation between follicular adenoma and carcinoma on Bethesda type IV lesions. This situation leads to many unnecessary surgical procedures because it is not possible to assure the benignity of the lesions, even when most of the specimens correspond to adenomas or even other benign lesions.The objective is this study is to establish if there are any US characteristics that would help us to predict the risk of malignancy of nodules with a pathological diagnosis of follicular neoplasm in order to achieve a more conservative management for non-suspicious nodules. Material and methodsWe studied 61 nodules in 61 patients (51 women and 10 men) that underwent thyroid surgery and had histopathological results of either follicular adenoma or carcinoma.Different US characteristics of the nodules were analysed (composition, echogenicity, margin, calcification status, the presence of halo and overall observer suspicion of malignancy) and were correlated with the histopathological analysis. ResultsWe have found a statistically significant association between the presence of calcifications, ill-defined borders and overall observer suspicion or impression (defined by well-known suspicious for malignancy ultrasonographic features, such as calcification, poorly defined margin, and a markedly hypoechoic solid nodule; and benign ultrasonographic features, such as predominantly cystic echogenic composition and the presence of a perinodular hypoechogenic halo) with follicular carcinoma. However all those features have shown low sensitivities in the present study (30%, 30% and 50%, respectively). On the other hand, the absence of halo sign has shown a sensitivity of 100% and a negative predictive value (NPV) of 100% in our study. ConclusionsThe presence of calcifications, ill-defined borders and the overall impression or suspicion of malignancy associate with a higher risk for follicular carcinoma in Bethesda type IV thyroid nodules but their absence do not allow to predict benignity in these nodules. Inversely, when a halo sign lesion is observed, benign follicular neoplasm should be considered.

Ultrasonic Characterization of Primary Squamous Cell Carcinoma of the Thyroid.

To identify the ultrasonographic characteristics of primary squamous cell carcinoma of the thyroid (PSCCT), and to assess the value of the 2015 American Thyroid Association (ATA) guideline and 2017 American College of Radiology (ACR) Thyroid Imaging, Reporting and Data System (TI-RADS) in the evaluation of this disease. Eight patients with 9 PSCCTs over a 20-year study period were enrolled. Ultrasonic characteristics including nodule echogenicity, composition, shape, margin, calcification, size, vascularity, and cervical lymphadenopathy were reviewed. All nodules were then evaluated by 2017 ACR TI-RADS and 2015 ATA guidelines. The average size of PSCCTs was 3.87 ± 1.41 cm. All PSCCTs were hypoechoic or very hypoechoic, solid nodules with intranodular vascularity. The average resistive index (RI) was 0.84 ± 0.18. Near half of PSCCTs (44.4%) demonstrated extrathyroidal extension. Taller-than-wide signs and cervical lymphadenopathy were observed in 33.3% of PSCCTs, and microcalcification was observed in 11.1% of them. All PSCCTs were classified as high suspicion patterns by 2015 ATA and recommended for fine-needle aspiration (FNA). Six PSCCTs (66.7%) were classified as grade 5 by 2017 ACR TI-RADS, while the remaining were grade 4. 88.9% of PSCCTs were recommended for FNA based on 2017 ACR TI-RADS. PSCCT has certain ultrasonic features, including relatively large, hypoechoic, or very hypoechoic solid nodules with intranodular vascularity and extrathyroidal extension. Both 2015 ATA and 2017 ACR TI-RADS could identify PSCCT as suspicious for malignancy.

Metastatic Clear Cell Renal Carcinoma with Benign Ultrasonographic Findings in the Thyroid Gland

Metastasis to the thyroid gland is rare, and the incidence of thyroid metastasis is from 1.4% to 3% for all thyroid malignancies. The most common metastatic malignancy to the thyroid gland is renal cell carcinoma. Ultrasonography is useful to assess the malignancy risk of thyroid nodules, and the ultrasonographic features of metastatic renal cell carcinoma in the thyroid gland are hypoechoic solid nodules with increased vascularity. Here, we report a case of metastatic clear cell renal carcinoma with benign ultrasonographic features and fine-needle aspiration cytology in the thyroid gland. A 76-year-old woman visited our hospital for surgical management of a growing left thyroid mass. Her history comprised previous left nephrectomy for an unknown reason. Thyroid ultrasonography revealed a well-defined, isoechoic, solid mass. Left thyroidectomy was performed, and the final diagnosis was metastatic clear cell renal carcinoma of the thyroid gland.

Report of A Case of Papillary Thyroid Carcinoma Following Intracranial Germinoma

Introduction The occurrence of second primary thyroid malignancy should be noticed in survivors of brain germinoma treated by irradiation. Case Report A patient with a history of intracranial germinoma who underwent chemoradiotherapy was referred to our endocrine clinic due to impotency and infertility. The patient received replacement therapy due to hypopituitarism. He returned to us 11 years after brain radiation with enlargement of the thyroid gland. Thyroid ultrasonography showed enlargement with a dominant 62*37 mm solid hypoechoic nodule in the right thyroid lobe. Several lymph nodes at both sides of the neck were seen. Total thyroidectomy revealed PTC with regional metastasis. Conclusion Endocrine disruption must be considered in adult cancer survivors and the importance of long-term follow-up should be emphasized in these patients.

Sonographic predictors of aggressive behavior in medullary thyroid carcinomas

ObjectiveTo identify the clinical and sonographic risk factors for aggressive behavior of Medullary Thyroid Carcinomas (MTCs). Material and methodsThis is a retrospective analysis. The informed consents were waived. Totally, 127 patients were selected from the database. Two radiologists were invited to review the clinical records and ultrasonic images and scored all the cases according to ACR TI-RADS, retrospectively. Kappa test was used to evaluate the consistency between the two reviewers. Logistic regression analysis was carried to identify the risk factors for aggressive behaviors of MTCs. Comparison of survival proportions between different groups were calculated by Kaplan–Meier method and log-rank test. ResultsFemale patients with MTCs were more commonly seen than male (1.7:1), male sex was a risk factor for both metastasis (OR: 4.471, P = 0.001) and perithyroidal invasion (OR = 4.674, P = 0.004). Consistency between the two reviewers were quite high (K value, 0.797–0.988). On sonograms, typical MTCs manifest as hypoechoic (96.9%) solid nodules (94.5%). Sex of patients (P = 0.001), margin (P = 0.003) and focality (P = 0.01) of the nodule were independent risk factors for metastasis, whereas sex of the patients (P = 0.004) and margin (P = 0.000) were independent risk factors for perithyroidal invasion. By Kaplan–Meier analysis, survival proportions different between groups with/without perithyroidal extension (P = 0.000) but not between groups with/without metastasis (P = 0.473). ConclusionHigh frequency ultrasound and TI-RADS were effective methods for preoperative diagnosis of MTC. Sex of the patients and margin of the nodule are common risk factors for both metastasis and perithyroidal invasion. Focality of the tumor is another independent risk factor for metastasis.