Papillary thyroid carcinoma in a branchial cleft cyst.

Branchial cleft cysts are congenital anomalies that form during fetal development and originate from the second branchial cleft. They typically manifest as painless masses on the side of the neck and can become symptomatic when infected. These cysts can create a cavity that may foster infection and, in rare instances, facilitate the spread of primary tumors. It is unusual to find ectopic thyroid tissue within a brachial cyst and it is even rarer to see papillary thyroid carcinoma developing from this tissue. Whenever physicians find a case of lateral neck cyst containing thyroid neoplasm without a known primary in the thyroid, there is always a confusion about whether it is a case of metastatic disease with an undetected primary tumor, or is a carcinoma originating from ectopic thyroid tissue. This is a case report of a papillary thyroid cancer that was unintentionally discovered inside a branchial cyst. So far, only five cases akin to this have been documented. There was no sign of an underlying primary thyroid tumor after the patient had a complete thyroidectomy and selected neck dissection, according to a comprehensive evaluation. This article touches on the development of thyroid tissue within branchial cysts and discusses the etiology of lateral neck tumors. The outcome for such patients appears to be favorable after cyst excision and total thyroidectomy. This article also emphasizes the importance of doing routine histopathological examinations on surgically removed samples that look benign.

Etiologies of lateral cervical masses are complex, most commonly these masses are branchial cleft cysts; however, metastatic thyroid carcinoma should be included in the differential. We report a case of lateral cystic neck mass in a 22-year-old female patient diagnosed as metastatic papillary thyroid carcinoma. The patient was diagnosed after she underwent surgery for branchial cleft cyst. The patient underwent thyroidectomy which revealed multifocal micropapillary thyroid carcinoma with capsular invasion and lymph node metastases. Radioactive iodine treatment was planned. Congenital malformations of the lateral neck may present themselves in the second and third decades of life. Ectopic thyroid tissue within a branchial cleft cyst may give rise to primary papillary carcinoma, as well as branchial cleft cyst may harbor metastases of primary thyroid papillary carcinoma. We classified our patient as a metastasis to the branchial cleft cyst rather than primary papillary carcinoma of the branchial cleft cyst.

Objective: 1) Describe the diagnostic dilemma of finding a thyroid carcinoma in a lateral neck mass without a primary. 2) Understand the etiological theories of branchial cleft cysts. 3) Be able to manage a patient with thyroid carcinoma in a lateral neck mass without a primary site identified. Method: We report a rare case of papillary thyroid carcinoma incidentally found within a branchial cleft cyst. Only 4 other cases have been described in the literature. A total thyroidectomy and selective neck dissection was performed and no evidence of occult primary disease was found after review of fine sections. Results: Branchial cleft cysts are the most common lateral neck masses. Ectopic thyroid tissue within a branchial cleft cyst is an unusual phenomenon and papillary thyroid carcinoma arising from this tissue is extremely rare. Clinicians are left with a diagnostic dilemma when presented with thyroid tissue neoplasm within a neck cyst in the absence of a thyroid primary—is this a case of metastatic disease with a missed primary or rather carcinoma arising in ectopic thyroid tissue? A thorough discussion of the etiologies of these lateral neck masses is reviewed including the embryogenesis of thyroid tissue in a branchial cleft cyst. Conclusion: The prognosis of patients with papillary thyroid carcinoma in lateral neck cysts without a primary site identified appears to be good following excision of the cyst and total thyroidectomy. Other management recommendations regarding these unique lateral neck malignancies are also presented.

We report a rare case of papillary thyroid carcinoma incidentally found within a branchial cleft cyst. Only four other cases have been described in the literature. A total thyroidectomy and selective neck dissection was performed, and no evidence of occult primary disease was found after review of fine sections. Branchial cleft cysts are the most common lateral neck masses. Ectopic thyroid tissue within a branchial cleft cyst is an unusual phenomenon, and papillary thyroid carcinoma arising from this tissue is extremely rare. Clinicians are left with a diagnostic dilemma when presented with thyroid tissue neoplasm within a neck cyst in the absence of a thyroid primary—is this a case of metastatic disease with a missed primary or rather carcinoma arising in ectopic thyroid tissue? A thorough discussion of the etiologies of these lateral neck masses is reviewed including the embryogenesis of thyroid tissue in a branchial cleft cyst. The prognosis of patients with papillary thyroid carcinoma in lateral neck cysts without a primary site identified appears to be good following excision of the cyst and total thyroidectomy. Other management recommendations regarding these unique lateral neck malignancies are also presented.

SummaryWe report a case of metastatic papillary thyroid carcinoma presenting with a recurrent right-sided cervical lymph node necrotic cyst. A 55-year-old woman presented with a 3-month history of a right-sided upper neck mass following an upper respiratory tract infection. Past medical history includes a right-sided nephrectomy secondary to a benign renal tumor and hypertension. She was evaluated by Otolaryngology, and fine-needle aspiration was performed. The mass recurred 2 months following aspiration. Ultrasound of the neck showed a 2.2 × 1.4 × 1.9 cm right cervical lymph node with a small fatty hilum but a thickened cortex. Neck computed tomography (CT) scan showed a well-defined 2.3 cm mass in the right upper neck corresponding to a necrotic cervical lymph node at level IIA. It also revealed a 7 mm calcified left thyroid nodule. Cytology revealed a moderate collection of murky fluid with mildly atypical cells presumed to be reactive given the clinical history of infection. The cyst had re-grown 2 months following aspiration. Excisional biopsy was performed and revealed metastatic classic papillary thyroid carcinoma (PTC). Subsequently, a total thyroidectomy and right neck dissection was performed. Pathology confirmed metastatic unifocal classic PTC of the right thyroid lobe and two lymph node metastases out of a total of 17 resected lymph nodes. The patient underwent radioactive iodine ablation. Subsequent I-131 radioiodine whole-body scan showed no evidence of metastases. In conclusion, metastatic PTC should be considered in the differential diagnosis of a recurrent solitary cystic cervical lymph node.Learning points:Metastatic PTC should be considered in the differential diagnosis of a recurrent solitary cystic cervical lymph node.A dedicated thyroid ultrasound is the preferred modality for identifying thyroid lesion over computed tomography.There is a risk of non-diagnostic cytology following FNA for cystic neck lesions, largely predicted by the cyst content of the nodule.

A case of papillary carcinoma arising in ectopic thyroid tissue within a branchial cleft cyst is described. A 46-year-old woman presented with a 2.0 x 2.0 cm mass in her left lateral neck. The excised mass showed a cystic lesion with a thyroid papillary carcinoma. Following a lateral cervical cystectomy, subsequent thyroid gland and lymph nodes dissections were performed. Pathological examination showed an adenomatous goiter and no primary carcinoma in the thyroid gland, as well as metastatic papillary carcinoma in the lymph nodes. Two cases of thyroid papillary carcinoma arising in ectopic thyroid tissue within a branchial cyst have been reported previously, but no lymph node metastases were recognized. The first case of papillary carcinoma arising in ectopic thyroid tissue within a branchial cleft cyst, and accompanied by lymph node metastasis is presented.

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Disclosure: N. Dhir: None. A. Safdar: None. M. Cillo: None.Introduction: Papillary thyroid cancer (PTC) is a common thyroid malignancy, which usually presents with the detection of a thyroid nodule on physical exam or imaging. It can metastasize to lymph nodes or other sites. PTC found in lymph nodes without a primary tumor in the thyroid gland is a rare occurrence. This can be distinguished from metastatic PTC by the absence of the primary tumor in the thyroid gland and the presence of thyroid tissue within the lymph node. Case Presentation: A 38-year-old woman with no significant past medical history presented to the clinic for a non-tender right submandibular mass. She noticed it 3 months prior to her visit and it has increased in size. Head and neck ultrasound revealed a complex cystic structure measuring up to 4.5 cm in the right side of the neck without any evidence of cervical lymphadenopathy. CT scan of neck showed no thyroid nodules but confirmed a complex right neck level IIa mass/lymph node with an enhancing solid component and thin wall cystic component. A dedicated thyroid ultrasound did not reveal any evidence of discrete thyroid nodules. Fine needle aspiration of the mass showed concerns for PTC, which was confirmed on the excisional biopsy revealing metastatic cystic PTC, 2.5 cm in largest dimension, without extranodal extension (1/7 lymph nodes were positive), and positive BRAF V600E mutation. The differential diagnosis included primary thyroid cancer that spread to this lateral lymph node versus ectopic thyroid cancer. Although ectopic thyroid cancer is a rare presentation, given the possibility she had a primary thyroid cancer that then spread to the lateral node, her risk of recurrence was deemed not to be insignificant. After shared decision making, she was recommended to proceed with total thyroidectomy with central and right sided lymph node dissection with adjuvant radioactive iodine therapy. She has yet to follow up on this recommendation and will likely prefer observation. Discussion: Ectopic PTC in a lymph node involves cancerous papillary thyroid cells arising from ectopic thyroid tissue within a lymph node. During embryogenesis, thyroid tissue could be displaced due to disrupted migration. There have been reports of ectopic thyroid tissue being found in the kidney, pancreas, lungs, and heart. The carcinoma could develop in the ectopic thyroid tissue, whether in a lymph node, the mediastinum, or even lungs, while the thyroid itself is normal. This is a rare and difficult to diagnose phenomenon. It is important to diagnose the source with appropriate imaging and careful histopathological and immunohistochemical analyses. Differentiating ectopic PTC from metastatic PTC is vital in providing an appropriate treatment plan and prognosis. This case highlights the importance of confirming the primary origin of PTC to further direct management.Presentation: Monday, July 14, 2025

Branchial cleft cysts are the most common lesions to arise laterally in the neck. Ectopic thyroid tissue within a branchial cleft cyst is rare, and a papillary carcinoma arising from this tissue is extremely rare. We present a case of a lateral neck cyst representing a primary papillary carcinoma that arose in ectopic thyroid tissue within a branchial cleft cyst in a 41-year-old woman. After the mass was surgically excised, thyroid ultrasonography, thyroid scintigraphy, and whole-body F18-fluorodeoxyglucose-positron emission tomography/computed tomography detected no abnormality. The negative findings notwithstanding, surgery on the thyroid gland was planned, but the patient refused it. Therefore, she was followed up with ultrasonography and scintigraphy for 5 years, during which time she exhibited no evidence of recurrence. Total thyroidectomy is still the primary option in such cases, but when it cannot be performed for any reason, vigilant follow-up is essential.

Lateral neck lesions in children are common and involve various infectious or inflammatory etiologies, as well as embryological remnants such as branchial cleft cysts. Although unusual, ectopic thyroid tissue may also present as a lateral neck mass. Here, we present an unusual case of a 15-year-old girl treated for an asymptomatic lateral neck mass that, after surgical removal, was found to be papillary thyroid carcinoma (PTC). However, after removal of the thyroid gland, no primary thyroid tumor was found. The question arose whether genethe lateral neck lesion was a lymph node metastasis without identifiable primary tumor by histological evaluation, or rather malignant degeneration of ectopic thyroid tissue. Total thyroidectomy was performed with postoperative adjuvant radioactive iodine ablation. Even though PTC in a lateral neck mass without a primary thyroid tumor has been described previously, pediatric cases have not been reported. In this report we share our experience on diagnosis, treatment and follow-up, and review the existing literature.

Papillary thyroid carcinoma is the most common thyroid malignancy and frequently metastasizes to regional lymph nodes. Occasionally, metastatic lymph nodes are palpable without the evidence of primary tumour. Papillary thyroid carcinoma of lateral neck cyst is a rare condition. It may arise from thyroid primary which underwent cystic degeneration or true malignant transformation of ectopic thyroid tissue. Herein, we reported two cases with preoperative diagnosis of benign lateral neck cyst but postoperative histopathological results showed primary papillary thyroid carcinoma. Ultrasonography and computed tomography of the neck in both cases showed no significant thyroid lesion. However, the patient in Case 2 was subjected for total thyroidectomy and histopathological results showed the origin of primary tumour. In conclusion, thorough investigations including total thyroidectomy are indicated in cases of papillary thyroid carcinoma of lateral neck cyst. This practice is to ensure that this type of thyroid cancer can be detected earlier because it has a very good prognosis if treated earlier.

Background: Ectopic thyroid tissue is a rare entity with a prevalence of 1 per 300,000 persons. Malignancy in ectopic thyroid tissue is reported in <1% of these cases.[1] We report a case of aggressive papillary carcinoma in ectopic thyroid gland in a patient with Graves’ disease.Case: A 65-year old woman was incidentally found to have a 3.1 cm mass with coarse calcifications in the superior mediastinum on CT scan of chest. Ultrasound confirmed the presence of hypoechoic mass which was separate from thyroid. Additionally, a 0.5cm TI-Rad 4 left thyroid lobe nodule was found. FNA of the mediastinal mass was suspicious for follicular thyroid neoplasm. Thyramir testing was positive for BRAF V600E and TERT c-124C>T mutations. Thyroid function tests showed frank hyperthyroidism and elevated thyroid stimulating immunoglobulins. Thyroid uptake and scan showed diffuse uptake of 67% at 24 hours.The patient underwent simultaneous excision of mediastinal mass and total thyroidectomy. The pathology of mediastinal mass showed papillary thyroid cancer with tall and sclerosis features with one involved lymph node. The pathology of thyroid gland did not show any malignancy. She was treated with 100 mCi I-131. Post treatment Whole Body Nuclear Scan after treatment revealed metastatic disease in left lower lung area.Discussion: Ectopic thyroid gland is usually found anywhere between forman caecum and mediastinum. It is rare to find ectopic thyroid tissue in the presence of eutopic thyroid gland which can create a diagnostic dilemma. Only a very few case reports of thyroid cancer arising from ectopic thyroid tissue have been reported. Our case is unique as the eutopic thyroid gland had Graves’ disease with no malignancy but the ectopic thyroid tissue developed aggressive papillary thyroid cancer. There are no specific guidelines for the management of carcinoma in ectopic thyroid glands, possibly due to the rarity of the condition. Our case has a clear metastasis to the lungs. However, it is important to differentiate ectopic thyroid tissue with carcinoma from thyroid cancer metastasis which can be difficult at times. Without specific guidelines for the management of cancer in ectopic thyroids, an individualised approach can be taken using the same therapeutic principals used in the management of eutopic thyroid cancer. Additionally, a finding of a normal thyroid gland or a benign condition in the thyroid gland should not exclude the diagnosis of malignancy in ectopic thyroid tissues.1) Vázquez, Oscar R., et al. “Ectopic papillary thyroid cancer with distant metastasis.” Case reports in endocrinology 2018 (2018).

Malignant lateral cervical cysts can be related to metastatic tumors or rarely to primary thyroid carcinoma arising in branchial cleft cysts. This study evaluates the expression of thyroid-associated transcription factor-1 (TTF-1) and p63 in three branchial cleft cysts and in two primary thyroid papillary carcinoma of branchial cleft cysts. TTF-1 was negative in the nuclei of the lining epithelia of branchial cleft cysts, but positive in the adjacent normal thyroid tissue, while TTF-1 was positive in the nuclei of the lining epithelia and in the nuclei of the papillae and follicles in branchial cleft cysts with ectopic thyroid carcinoma. P63 was positive in the nuclei of the lining epithelia of branchial cleft cysts, but negative in the adjacent normal thyroid tissue. Papillary thyroid carcinoma of branchial cleft cysts displayed p63-positive foci. In conclusion, our results demonstrate that TTF-1 cannot distinguish between primary and metastatic tumors of branchial cleft cysts. The detection of p63 in papillary thyroid carcinomas of branchial cleft cysts could suggest that p63 contributes to the onset of this tumor. It is really important to evaluate if the case has a metastatic derivation or represents papillary thyroid carcinoma arising in ectopic thyroid tissue in a branchial cleft cyst.

IntroductionMultiple primary tumors are defined as the presence of two primary tumors of different histologies in the same individual, which can be diagnosed at the same time or at different times. We present a rare case of papillary thyroid cancer (PTC) with pulmonary metastasis and lung adenocarcinoma diagnosed simultaneously and highlight the importance of identifying multiple primary cancers to guide management and improve patient outcomes.Clinical CaseA 57-year-old female with no prior history of malignancy was found to have a 12 mm left upper lobe lung nodule on CT chest as a part of evaluation of worsening cough. A fluorodeoxyglucose PET scan showed increased uptake in the left upper lobe nodule as well as a hypermetabolic thyroid nodule in the right thyroid lobe. She underwent a thoracoscopy, wedge resection, and left lung lobectomy with lymph node dissection, and pathology revealed adenocarcinoma of the lung as well as incidentally found PTC. Subsequently, thyroid ultrasound was obtained which showed a right upper mid-pole thyroid nodule measuring 1.7 cm. She underwent a total thyroidectomy, and pathology showed PTC, tall cell variant in the right lobe, with largest tumor dimension 1.5 cm with no extrathyroidal extension, no lymphatic, and no vascular invasion.A nuclear uptake scan post thyroidectomy showed focal uptake in the thyroid corresponding to residual thyroid tissue, without evidence of metastatic disease. She subsequently received 152.6 mCi of radioactive iodine (RAI). A post-therapy scan obtained one week later showed no new uptake. After RAI, her thyroglobulin antibody remained negative and thyroglobulin became undetectable. She remains on levothyroxine therapy with her TSH at target of 0.1-0.4 U/L. However, she unfortunately had recurrent disease of her lung adenocarcinoma and is continuing to undergo treatment with chemotherapyConclusionPTC is the most common type of differentiated thyroid cancer and generally has a better prognosis than other types of thyroid cancer given its indolent course. Histologic subtype, presence of extra thyroidal extension, lymph node involvement, and distant metastasis play a role in prognosis, and PTC metastasizes to the lungs in about 5% of cases. Clinicians should be aware of the possibility of multiple primary tumors, and the use of diagnostic modalities like FDG-PET and tissue biopsy can help differentiate a second primary tumor from metastatic disease. Radioactive iodine therapy (RAI) for management of differentiated thyroid carcinoma has been linked to predisposition to other primary malignancies such as leukemia and lymphoma, however our patient was found to have both malignancies simultaneously prior to receiving RAI. This suggests the possibility of genetic susceptibility or alterations in the immune constituency. Further studies are needed to analyze the genetic and environmental factors that lead to development of two primary tumors in certain individuals.Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

Branchial Cleft Cyst as the Initial Impression of a Metastatic Thyroid Papillary Carcinoma: Two Case Reports