Midline Neck Mass Research Articles

PSAT252 Primary Papillary Thyroid Carcinoma Arising from a Thyroglossal Duct Cyst

Abstract Background Thyroglossal duct cysts (TGDC) are remnants of the thyroglossal duct tract that do not atrophy and disappear, instead undergoing cystic expansion and often presenting as a midline neck mass. Rarely, carcinomas of the thyroglossal duct cyst occur, either arising as a primary carcinoma or as a cystic metastasis from a primary thyroid cancer; the former are particularly rare. These thyroglossal duct cyst carcinomas most commonly present in the adult population. Case Report We present the case of a 32-year-old female without any significant past medical history who presented with a non-tender midline neck mass identified as a thyroglossal duct cyst and completely excised; pathology results were positive for a primary papillary thyroid carcinoma with a tumor measuring 1.3 cm in diameter within the TGDC. Thyroid Ultrasound also showed the presence of two nodules measuring 1.4 cm on the right and 1.2 cm on the left, respectively, with fine needle aspiration (FNA) of both the nodules confirming papillary thyroid carcinoma as well. Lymph node FNA was negative for metastatic carcinoma. The patient underwent a thyroidectomy which definitively confirmed both a classic papillary carcinoma as well as an encapsulated, non-invasive follicular variant. In keeping with the original finding of the patient having a primary thyroglossal duct cyst carcinoma, samples from the thyroidectomy had negative tumor margins, and were also negative for any angioinvasion, lymphatic invasion, or extrathyroidal extension. Conclusion While thyroglossal duct cysts are the most common type of congenital neck cyst, primary carcinomas arising from thyroglossal duct cysts are rare. Masses that occur anywhere along the thyroglossal duct tract should be investigated for malignancy, with additional investigation of the thyroid gland for either a primary or secondary thyroid cancer. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

PSAT282 A Case of Papillary Thyroid Cancer in a Thyroglossal Duct Cyst

Abstract Background Thyroglossal duct cysts (TGDC) are common congenital neck anomalies. They persist through adulthood in 7% of the general population. Associated malignancy is rare, occurring in <1% of cases. Over 90% of such malignancies are papillary thyroid carcinoma (PTC). Twenty to 60% of patients with TGDC malignancies are found to have concomitant cancer in the thyroid. The rarity of TGDC malignancy make its management particularly challenging, given limited long term outcome data. We describe a case of a 4cm TGDC PTC. Case A 49-year-old female with a history of autoimmune thyroid disease presented for evaluation of a goiter. She reported 6 months of painful midline neck swelling. No family history of thyroid cancer and she had no history of radiation to her head or neck. She denied swallowing, dyspnea, or hoarseness. Physical exam was notable for a mildly tender, firm 2.5 cm submental midline neck mass overlying the hyoid. TSH was normal and thyroid peroxidase antibody was >1000 (n: <5 IU/mL). Neck ultrasound showed a 3.7×2.5×1.6 cm mixed solid/cystic midline neck mass and a mildly enlarged, heterogeneous, and vascular thyroid without discrete intrathyroidal nodules. A neck CT with contrast indicated that the midline mass was heterogeneously enhancing with tiny internal cystic spaces. The differential diagnosis included an infected thyroglossal duct cyst versus malignant transformation. Fine needle aspiration of the mass was suggestive of PTC. The patient underwent the Sistrunk procedure, with excision of the thyroglossal duct cyst, the middle of the hyoid bone, and the tissue surrounding the thyroglossal tract. Final pathology was consistent with a 4 cm PTC, classical type, without lymphatic, vascular or perineural invasion. Surgical margins were negative for malignancy. Two months postoperatively, TSH remained normal, and the thyroglobulin (TG) level was 78 with negative TG antibodies. She declined a thyroidectomy. Conclusion To date, there is no consensus guideline regarding optimal management for malignancy involving TGDC. Studies suggest that surgical decision making be based on patient risk stratification. High risk factors include age older than 45 years, tumor >4 cm in size, extension of tumor to adjacent soft tissue, and/or the presence of nodal or distant metastases. In high-risk patients, treatment with Sistrunk procedure combined with thyroidectomy, neck dissection and radioactive iodine therapy have shown excellent results. In younger than 45 years with tumor size <1.5 cm, without extension beyond cyst wall and normal thyroid ultrasound Sistrunk procedure alone might be sufficient. Despite low risk factors patients should still be advised to have thyroidectomy as there could be a 20% risk of coexisting thyroid cancer. Additional longitudinal studies are needed to confirm that this approach leads to optimal long-term outcomes for patients with TGDC-associated malignancy. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

PSAT286 A Rare Case of Papillary Thyroid Cancer of the Thyroglossal Duct Cyst with Benign Thyroid

Abstract Introduction While the thyroglossal duct cyst (TGDC) is the most commonly seen midline neck mass, thyroglossal duct cyst carcinoma is rare (1-2%) with only a few hundred cases published in the literature. The disease can be challenging to diagnose and treat because most TGDC carcinoma are diagnosed post-operatively and data is limited regarding the extent of surgical resection, adjuvant therapy and long-term outcomes. We report a case of papillary thyroid carcinoma arising from TGDC without any evidence of disease in the thyroid gland. Case Report A 31-year-old male presented with complaints of progressively worsening dysphagia and weight loss for 4 months. An initial CT neck with contrast revealed a soft tissue mass along the anterior aspect of the thyroid cartilage measuring 3.4×2.0×2.2 cm that extended anteriorly from the base of the tongue, favoring a thyroglossal duct cyst. The thyroid gland appeared normal on this imaging. He was given a 2-week course of antibiotics and pantoprazole with no improvement in his symptoms. He underwent a thyroid ultrasound, which showed a large hypoechoic mass, partially cystic, anterior to thyroid. FNA of the TGDC was suspicious for papillary thyroid cancer. Follow-up CT scan redemonstrated known TGDC with increased size of adjacent lymph nodes, concerning for metastasis. Given FNA results, regional lymph node involvement, and the patient's symptoms, he underwent successful Sistrunk procedure for TGDC removal. He declined to wait for intraoperative frozen pathology and opted to discuss pathology and next steps after surgery. Pathology of the TGDC confirmed papillary thyroid cancer (conventional type) with uninvolved margins and metastasis to one of four lymph nodes with the largest lymph node being 7 mm. At the tumor board conference, it was recommended he further undergo a total thyroidectomy with possible post-operative radioactive iodine (RAI) treatment. He underwent a total thyroidectomy, and pathology showed benign thyroid gland with a few colloid cysts. Post-operatively, he was started on levothyroxine. He did not have any improvement in dysphagia following both surgeries. After extensive discussion of the risks and benefits of RAI, the patient chose to defer RAI treatment until further evaluation of his dysphagia was completed. Ultimately, the decision was made to monitor with serial ultrasounds and thyroglobulin levels. Conclusion Optimal treatment of TGDC carcinoma is debatable. A Sistrunk procedure involving resection of cyst plus mid-portion of hyoid bone is universally recommended for adequate excision of the cyst. However, no clear consensus guidelines exist for further management with total thyroidectomy and/or post-operative RAI. Total thyroidectomy permits excision of unsuspected thyroid carcinomas and enables a better follow-up. However, decisions can vary based on extent of disease, tumor characteristics, demographics, and patient preferences. Management decisions should be made on an individualized basis, using a multidisciplinary and shared decision-making approach. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

Thyroglossal duct cyst with hoarseness as the sole symptom and an intralaryngeal extension masquerading as a laryngeal mass: Clinical experience and literature review.

A thyroglossal duct cyst is the most common congenital disease in the neck. There are two age groups usually associated with thyroglossal duct cysts: 1-11years in children and 30-60years in adults. These midline neck masses are typically located anteriorly in the neck, inferior to the hyoid bone. We report an extremely rare case of an intralaryngeal thyroglossal duct cyst without a neck mass, presenting with hoarseness as the sole symptom. A 64-year-old man presented with a 3-month history of hoarseness. On physical examination, no neck mass or swelling was observed during cervical palpation. Laryngostroboscopy revealed a large submucosal mass in the right glottis and supraglottis, and mobility of the right vocal cord was restricted. Surgery was performed via an external approach to completely resect the cyst, together with the middle part of the hyoid bone. Histopathologic examination of the cyst led to a diagnosis of thyroglossal duct cyst. The patient recovered well and his voice returned to normal. Attention should be paid to the occurrence of rare types of thyroglossal duct cyst in unusual clinical sites. Adequate radiological examinations should be performed, and reading the computed tomography or magnetic resonance imaging scans carefully before surgery is important to avoid misdiagnosis.

Dermoid cyst of parotid gland; Report of a rare entity with literature review.

Dermoid cysts are developmental cysts in young adults that are very uncommon in head and neck area. In oral and maxillofacial area the cysts are mainly present in the submental triangle and in floor of mouth. In the neck dermoid cysts usually present as midline neck mass. Parotid gland is extremely rare site at which the dermoid cysts develop. There are only 19 reported cases till date. Superficial parotidectomy is the suggested surgical treatment, however sometimes enucleation is all that is needed. We present a rare case of this entity which was pre-operatively diagnosed as pleomorphic adenoma on Fine Needle Aspiration Cytology.

Rare Presentation of Left‐sided Thyroglossal Duct: A Case Report on Embryological Persistence

Thyroglossal duct (TGD) plays an important role in guiding the embryonic development and migration of the thyroid gland down the midline of the trachea. By the tenth week of gestation, TGD is completely obliterated with the thyroid gland in its proper position. In about 7% of the population, TGD persists and forms a thyroglossal duct cyst (TGDC) within the midline of the pretracheal neck region and often presents as the most common congenital midline neck mass. A rare finding of TGD from posterior base of the tongue to left‐lateral pyramidal lobe, outside its normal midline pathway, was observed in a 92‐year‐old male during routine cadaver dissection of first year medical student’s curriculum at Oakland University William Beaumont School of Medicine. Upon further inspection of the thyroid, there was no evidence of hyperplasia or lesion in the thyroid or the thyroglossal duct itself. The thyroid and associated structures were studied by first year medical students during dissection in 25 formalin fixed cadavers (13 male, 12 female, average age of 76‐years‐old). Four of the 25 cadavers did not present with a thyroid due to previous thyroidectomy. The pyramidal lobe was observed in four of the 25 cadavers (19.05%), and a thyroglossal duct was observed in 3 of the 4 cadavers in the pyramidal lobe subgroup. Within this subgroup, only one cadaver displayed a left‐sided thyroglossal duct. Currently, clinical literature suggest findings of TGDCs in four general regions of intralingual, suprahyoid, thyrohyoid, and suprasternal, but all within the midline pathway of TGD. This case finding reinforces the importance of CT scanning when treating patients with TGDC by surgical removal.

Papillary carcinoma arising from a thyroglossal duct cyst: A case report and literature review

IntroductionPapillary carcinoma originating from a thyroglossal cyst is rare and peculiar, with majority of cases detected after surgery. Despite an excellent prognosis, its management remains controversial. Herein, we report the case of a 53-year-old woman who underwent Sistrunk procedure for a thyroglossal duct cyst and was subsequently confirmed to have papillary thyroid carcinoma.Presentation of caseA 53-year-old woman presented with an anterior midline neck mass for 7 years. The patient had no symptoms of hypo-or hyperthyroidism. Additionally, she had no history of compressive symptoms. Neck ultrasound revealed a well-defined 3.5 cm × 2.2 cm × 3 cm-sized cystic lesion inferior to the hyoid bone, with a peripheral solid component. Neck computed tomography revealed a well-defined 3.7 cm × 3.4 cm × 2.7 cm-sized cystic lesion with an enhanced central solid component with focal calcifications, inferior to the hyoid bone, and in contact with the anterior wall of the thyroid cartilage. Sistrunk procedure was performed. The patient was then diagnosed with papillary thyroid carcinoma with TNM stage pT2 and underwent total thyroidectomy as a follow-up procedure.DiscussionThyroglossal duct cyst carcinoma is usually detected in the fourth decade of life with a higher prevalence in women. Neck ultrasound is performed during the initial radiological workup to assess the cyst and confirm the presence of the thyroid gland.ConclusionThe Sistrunk procedure is highly effective in low-risk patients. A more aggressive approach is required for high-risk patients.

Large non-functioning substernal parathyroid cyst: A case report and review of the literature.

ObjectivesParathyroid cysts are rare benign lesions of the head and neck that account for less than 1% of cystic neck masses. We present a rare case of a large 6 cm substernal parathyroid cyst.Presentation of caseAn otherwise healthy 65 year-old female presented to the otolaryngology clinic for evaluation of an anterior, midline neck mass. On physical exam, she was noted to have a fullness in the anterior neck extending to the sternal notch. CT demonstrated an enlarged thyroid with a cyst extending to the aortic arch. Initial evaluation suggested a bilateral goiter with substernal extension. The cyst was managed with drainage and observation. After two years of continued growth, the patient underwent a left thyroid lobectomy and mediastinal mass resection via the cervical approach. Final pathology was consistent with a parathyroid cyst.ConclusionsParathyroid cysts are a rare cause of neck mass in an adult, and a 6 cm substernal parathyroid cyst represents an unusual site and size for these cysts. Parathyroid cysts are not often considered on the differential of neck and mediastinal cystic lesions. However, appropriate steps should be taken to ensure a proper diagnosis for any cystic lesion in the neck.

Incidence of midline neck mass (A retrospective cyto-morphological study, at Jorhat Medical College, Assam)

Introduction: Midline neck mass presents varying degrees of enlargements in front of the neck encompasses thyroglossal duct/cyst, solitary thyroid cyst, thyroid neoplasm.Objective: To find out the incidence of midline mass by FNAC in Jorhat Medical College & Hospital from the period October 2020 to September 2021.Materials and Method: one year retrospective, qualitative cross sectional, observational study done in 72 nos.of different cases of midline mass and FNAC was the first mode of examination in all cases referred to us.Result: Reporting of the cases was followed by New Bethesda system of reporting thyroid cytopathology (TBSRTC) which offers very clean concept clinically well explainable to our clinician. On FNAC reporting 60-70% of cases had simple colloid goiter, followed by hyperthyroidism that was associated with huge nodularity and thyrotoxic features.Few cases of AUS/FLUS were reported as per criteria laid down by TBSRTC Bethesda grading.Conclusion: In this study, goiter in females which constitute nearly 70-80% between the 3rd and 4th decades of life. FNAC resulted with 97 % sensitivity about 95 % specificity with high Positive predictive value. FNAC found to be most economical, quick and gold standard, easy to interpret by both the pathologist and the clinician till date.

Pyramidal Lobe Nodule or Thyroglossal Duct Lesion? Approach to Diagnosis and Treatment

A 63-year-old woman presented with a 12-year history of an enlarging high anterior midline neck mass. Surgical history was notable for left hemithyroidectomy 17 years prior for multinodular hyperplasia. She reported intermittent globus sensation but was otherwise asymptomatic. Her examination demonstrated a midline neck mass overlying the thyrohyoid membrane that elevated with tongue protrusion (Fig. 1). Ultrasound showed a solid mass, isoechoic to the thyroid, with cyst components. Computed tomography imaging showed a 1.5 × 2.0 × 1.7–cm heterogeneous enhancing lesion with multiple nodules high in the midline (Fig.

Recurrent Graves’ Disease in Thyroglossal Duct Following Total Thyroidectomy

Introduction: A 46-year-old female with a past medical history of Graves’ disease refractory to medical management, thus requiring total thyroidectomy presented to clinic for recurrence of her hyperthyroidism and an increasing midline neck mass two years after her index operation. Case Description: CT imaging of the neck mass revealed a locally extensive enhancing abnormality immediately anterior to the hyoid bone within the infrahyoid muscles measuring 1.4x.1.9x4.0 cm. This was consistent with an exceedingly rare proliferation of a thyroglossal duct remnant secondary to recurrence of the patient’s Graves’ disease. The patient was treated with surgical resection of the neck mass shown to be ectopic Graves’ activated thyroid tissue by pathology. The patient was restarted on thyroid hormone replacement therapy and has remained euthyroid to date following surgical resection. Conclusion: The incidence of this event is estimated to be approximately one per a million persons and thus is a rare occurrence in endocrinology. This case highlights the potential shortcomings of surgical management of Graves’ disease. Following surgical resection, the autoimmune status of the patient remains unchanged. Ectopic thyroid tissue can be found anywhere along the embryologic descent of the thyroid gland and as low as the mediastinum. Thus, patients treated with total thyroidectomy should still be monitored regularly for recurrence of Graves’ disease secondary to ectopic thyroid tissue.

Transoral sistrunk procedure

Thyroglossal duct cysts are a common congenital, midline neck mass. Surgical excision of the mass and its embryonic tract including the middle portion of the hyoid bone and suprahyoid musculature, is known as the Sistrunk procedure and is a key to preventing recurrence. One of the few drawbacks of this surgical approach is that can leave aesthetically noticeable scars. A novel way to avoid such a scar is to use a transoral endoscopic vestibular approach similar to what is used in the transoral endoscopic thyroidectomy vestibular approach. This approach is both safe and effective in the appropriately selected patient. It allows for adequate resection of the thyroglossal duct cyst and its tract while avoiding a cervical incision.

Symptomatic Thyroglossal Duct Cyst Presenting With Synchronous and Localized Tongue Base Extranodal Mantle Cell Lymphoma. A Unique Case Report Demonstrating Lymphoma Colonization of Cyst Wall, Potentially Relating to a Persistent Embryological Foramen Cecum Remnant

A 77-year-old male presented with a progressively enlarging midline neck mass. On further investigation he was found to have synchronous thyroglossal duct cyst and extranodal mantle cell lymphoma (MCL) localized to the base of tongue. Both pathologies were managed simultaneously with a surgical approach and the patient remained in clinical remission at the time of publication without indication for systemic oncological treatment. Histology revealed primary extranodal nonblastoid MCL forming a base of tongue mass, with colonization of the thyroglossal duct cyst. Lymphoma was also found in the epithelium of a crypt-like tract traversing one of the tongue base tumor sections. This tract was anatomically and histologically consistent with documented descriptions of the foramen cecum. This case report illustrates a previously undescribed temporal, clinical, and histological association between a base of tongue MCL and symptomatic thyroglossal duct cyst. We provide evidence for a potential causal relationship for the presentation of the thyroglossal duct cyst as a result of oropharyngeal MCL, in the absence of clinical and histological evidence of disseminated disease, directly infiltrating from its tongue base origin to the infrahyoid neck region, potentially via an embryologic foramen cecum remnant. We also highlight the crucial role of the histopathologist in multidisciplinary clinicopathological discussion in demonstrating how fundamental embryological and microanatomical relationships can unite apparently separate diseases.

Endoscopically-Assisted Scar-Free Midline Neck Mass Excision.

Traditional open surgery is indicated for the treatment of selected tumor subsites in the head and neck. However, it can cause major cosmetic problems and functional pathologies. The endoscopically-assisted transoral approach is increasingly preferred in some surgical fields due to its superior cosmetic and functional outcomes. Nonetheless, endoscopically-assisted transoral approach is not yet standard in the head and neck due to their anatomical complexity. The transoral surgical approach has been used for head and neck masses since the 1960s, and its application continues to evolve with changing disease conditions and recent innovations in surgical instruments. The potential for wide application of transoral surgery continues to be investigated, with a focus on minimizing occurrence of the complications. This review presents details of the surgical procedure and postoperative clinical outcomes, as well as endoscopically-assisted scar-free techniques for the resection of midline neck masses.

Thyroglossal duct cyst presenting as life-threatening airway obstruction in a neonate

Thyroglossal duct cysts are the most common congenital abnormality in the neck, accounting for 70-75% of midline neck masses in children [1]. Late in the 4th week of gestation, the thyroid anlage develops as a small, solid mass of endoderm proliferating at the foramen cecum. As the thyroid anlage descends caudally in the neck, it maintains an attachment to the site of origin at the level of the foramen cecum of the tongue via the thyroglossal duct [2]. The thyroglossal duct typically involutes and atrophies between 7 and 10 weeks of gestation by the time the thyroid gland reaches its final position inferior to the cricoid cartilage [2]. The source of TGDC is believed to be persistent remnants of the thyroglossal duct. Due to the communication of the duct to the mouth via the foramen cecum, thyroglossal cysts can become infected with oral flora. One-third of patients of all ages will present with a concurrent or prior infection, and one-quarter will present with a draining sinus from spontaneous or incisional drainage of an abscess [3]. The cysts occur almost equally in both sexes [4,5].

Proposed ultrasound algorithm to differentiate thyroglossal duct and dermoid cysts

Objective1) To assess reproducibility of the previously established SIST score. 2) To determine inter-observer agreement in using ultrasound (US) characteristics to differentiate thyroglossal duct cyst (TGDC) from dermoid cysts (DC) 3) Improve the method used to pre-operatively differentiate TGDC from DC. Study designRetrospective chart review. SettingTertiary care pediatric hospital. Subjects and MethodsAn electronic medical record was queried to identify children with midline neck masses who underwent pre-operative neck US and had a histopathologic diagnosis of either TGDC or DC. Two pediatric radiologists, blinded to the pathologic diagnosis, evaluated the US images and documented the presence of pre-determined characteristics of each mass. Potential differentiating factors were analyzed for their predictive power. The SIST (septations, irregular walls, solid components = TGDC) score was determined as well as inter-observer agreement. Using the characteristics that had significant predictive power, we used the data to develop an algorithm to improve predicting cyst type. ResultsPathologically, there were 47 TGDC and 25 DC. The inter-observer agreement about the pathologic diagnosis between the two radiologists was substantial, K = 0.66. Overall, the SIST score predicted the correct diagnosis 67% of the time. Radiologist 1 and radiologist 2 were more accurate than the SIST score alone, making the correct diagnosis 96% and 86% of the time, respectively. In our study, we found that the most important US characteristics in differentiating TGDC and DC are: internal Septations, depth relative to Strap muscles, Shape and Solid parts (4 S algorithm). The SIST score criteria were individually shown to be significant and sensitive in recognizing DC, however, they were not specific and often misclassified TGDC as DC. We developed a new sequential filtering algorithm that more accurately differentiates cysts. This new algorithm uses step-wise filtering of characteristics, first for Septations, then for depth to Straps, then Shape of the cyst and lastly Solid parts (4 S algorithm). This algorithm correctly categorized cyst type in 100% of patients in our study. ConclusionsPre-operatively differentiating TGDC and DC continues to be a challenge. Using our 4 S algorithm, we can more definitively differentiate TGDC from DC compared to the SIST score. All SIST score characteristics were significant and sensitive in detecting dermoid cysts, however, not very specific. The radiologists’ judgment and accuracy was better than the SIST score. The 4 S algorithm uses sequential filtering of important characteristics: Septations, depth to Straps, Shape of cyst and lastly Solid parts to improve diagnostic accuracy.

Prenatal Imaging Findings Predict Obstructive Fetal Airways Requiring EXIT.

Detection of fetal airway compromise through imaging raises the possible need for ex utero intrapartum treatment (EXIT) procedures. Despite EXIT procedures involving massive resource utilization and posing increased risk to the mother, decisions for EXIT are usually based on anecdotal experience. Our objectives were to analyze prenatal consultations with potential fetal airway obstruction for imaging and obstetric findings used to determine management strategy. Retrospective chart review was performed for prenatal abnormal fetal airway consults between 2004-2019 at a quaternary pediatric facility. Data collected included demographics, imaging characteristics, delivery information, and airway management. Our primary outcome was EXIT performance and the secondary outcome was postnatal airway management. Fisher's exact test was used to compare management decisions, outcomes, and imaging findings. Thirty-seven patients met inclusion criteria. The most common diagnoses observed were lymphatic malformation, teratoma, and micrognathia. Of the imaging findings collected, only midline neck mass location was associated with EXIT procedure performance. Factors associated with invasive airway support at birth were mass-induced in-utero neck extension and neck vessel compression, polyhydramnios, and micrognathia. Multidisciplinary input and interpretation of prenatal imaging can guide management of fetal airway-related pathology. EXIT is an overall safe procedure and can decrease risk due to airway obstruction at birth. We identified in-utero neck extension, neck vessel compression, micrognathia, and polyhydramnios as better indicators of a need for invasive airways measures at birth and suggest use of these criteria in combination with clinical judgement when recommending EXIT. 4 Laryngoscope, 131:E1357-E1362, 2021.

MON-438 Papillary Thyroid Carcinoma Arising in a Thyroglossal Duct Cyst: A Case Report

Introduction: Thyroglossal duct cysts (TGDCs) are uncommon benign congenital entities. Rarely, thyroid carcinoma can arise from a TGDC; the most common being papillary thyroid carcinoma (PTC). Similar to TGDC, carcinomas originating within them can present as an asymptomatic midline neck mass. Signs of malignancy include dysphagia, dysphonia, weight loss, and rapid growth. Given the rarity of TGDC carcinomas, clinical management remains controversial, particularly regarding the requirement for total thyroidectomy. Case: A 52-year-old female with history of an anterior central neck mass initially noted in 2017. A 0.3-cm left lobe mid-segment cyst and a complex thyroglossal avascular simple cyst measuring 2.4 × 1.1 × 1.8 cm was observed during ultrasound (US). She presented to the endocrinology clinic in April 2019 due to progressive enlargement of the mass.Repeat thyroid US revealed that the cystic structure had become complex with a peripheral solid component and measured 3.3 × 2.1 × 2.2 cm. FNA was performed and found to be suspicious for PTC (Bethesda category V) and positive for the BRAF V600E mutation.Patient was referred for surgical evaluation. Physical examination revealed a midline anterior 10-cm, painless, and fixed mass above the thyroid that moved with deglutition and tongue protrusion. Contrast computed tomography scan showed a large multiloculated cystic structure measuring 4.1 × 4.4 × 5.9 cm. A lobulated soft tissue mass measuring 2.2 × 2.4 × 3.0 cm was noted internally along the inferior margin of the cyst. She underwent en-block resection of the TGDC in addition to a total thyroidectomy. Histopathological examination identified a 7.5 × 5.5 × 5.0 cm cystic mass with fluctuation and a firm, solid area in the lower portion measuring 2.6 × 2.4 cm. Thyroid gland examination was otherwise unremarkable. No areas of extension of the mass into the thyroid tissue were clearly identified and no other gross lesions were observed. The solid area within TGDC contained a tumor with findings characteristic of PTC. Postoperatively, she was placed on thyroid hormone replacement therapy. Conclusion: The main difficulty encountered with cancer developing from TGDC is that the diagnosis is usually made during surgery and from definitive pathological samples. The most common surgical procedure used is the Sistrunk procedure. Some studies have suggested that this procedure alone is an adequate therapy, but others advocate the need for total thyroidectomy. The Sistrunk procedure is considered to be appropriate for low-risk patients, but high-risk patients must undergo total thyroidectomy. The decision to perform a total thyroidectomy in this patient was based on her high-risk classification due to: age, sex, cyst size, and a positive FNA for malignancy. Follow-up includes an annual physical examination, thyroglobulin levels, and an US every 6 months during the first year and annually thereafter.

SUN-618 An Unusual Case of Papillary Thyroid Cancer within a Thyroglossal Duct Cyst

Background: During gestation, the thyroid gland arises from endodermal tissues, and starts at the foramen cecum, then descends into the neck through the thyroglossal duct, and disappears at 8-10 weeks of gestation. Thyroglossal duct cysts arise from incomplete obliteration of the thyroglossal duct, and may contain thyroid tissue. Although the incidence of thyroid cancer has been rising, it is still relatively uncommon compared to other cancers, with papillary thyroid carcinoma being the most common type. However, in rare cases, thyroid carcinoma can occur within the thyroglossal duct cyst. We present a rare case of a young female with papillary thyroid carcinoma within a thyroglossal duct cyst. Case Presentation: A 28-year old female noticed an enlarging midline neck mass over the course of 5 years. She was initially evaluated by otolaryngology. CT neck revealed a heterogeneous large midline neck mass, measuring 5.7 x 3.6 x 4.99cm, which was separate from the thyroid gland. Submandibular lymph nodes were also enlarged. Pathology of core tissue biopsy of the mass demonstrated papillary thyroid carcinoma. She underwent thyroglossal duct cyst resection and total thyroidectomy with neck dissection. Pathology report was positive for papillary thyroid carcinoma, arising from thyroglossal duct cyst measuring 4.2cm. Three out of 16 lymph nodes were positive for papillary thyroid carcinoma. Thyroid gland had no evidence of malignancy. Postoperatively, thyroid hormone suppression therapy was started and she was treated with radioactive iodine ablation. Discussion: Thyroglossal duct cysts are the most common abnormalities in thyroid gland development. They are usually managed with excision, specifically the Sistrunk procedure, where the cyst, along with the entire tract and part of the hyoid bone is excised. In rare cases, thyroid cancer can arise within the thyroglossal duct cyst. When this occurs, management can sometimes be controversial, as there are no specific guidelines, and severity of disease varies. It is important to recognize that evaluation of these type of patients should include the thyroid and regional lymph nodes, in order to ensure that the thyroglossal duct cyst carcinoma is primary, and not a metastasis from a primary thyroid carcinoma. In cases where the malignancy is confined to the cyst, the Sistrunk procedure alone can be done. If malignancy is found in the thyroid and regional lymph nodes, the Sistrunk procedure in addition to total thyroidectomy is completed, and then post-operative management is the same as for differentiated thyroid cancer including radioactive iodine ablation. References Pellegriti G, Lumera G, Malandrino P, et al., Thyroid Cancer in Thyroglossal Duct Cysts Requires a Specific Approach due to Its Unpredictable Extension, JCEM, Volume 98, Issue 2, 1 February 2013, Pages 458-465.

Preoperative ultrasound for the diagnosis of thyroglossal duct cysts: A validation study

ObjectivesTo evaluate the use of ultrasound to distinguish between thyroglossal duct cysts (TGDC) and dermoid cysts (DC) for surgical planning. To validate the SIST (septae + irregular wall + solid components = TGDC) scoring system proposed by Oyewumi et al. [1]. MethodsThis was a retrospective chart review of pediatric patients with midline neck masses who presented between the years of 2005 and 2014 and underwent preoperative ultrasound and surgical resection. Two pediatric radiologists blinded to diagnosis reviewed each US for 14 separate characteristics. According to the SIST scoring system, one point was given for each of the following: internal septae, irregular walls, and solid components. Results45 patients met inclusion criteria. Final pathologic diagnosis showed 29 patients had TGDC, 16 had DC. The majority of patients with both TGDC and DC earned SIST scores of 0. ConclusionWhile ultrasound remains a useful part of the work-up of lesions of the head and neck in children, this small retrospective study was not able to validate the previously proposed SIST scoring system None of the parameters discussed in the original paper was found to be a statistically significant determinant of TGDC.