A diagnostic pitfall: papillary adenocarcinoma arising in ectopic thyroid tissue within a branchial cyst

A case of thyroid papillary carcinoma arising in ectopic thyroid tissue within a branchial cleft cyst is described. Complete dissection of the thyroid gland was necessary to rule out the differential diagnosis of primary thyroid carcinoma. The thyroglossal duct tract is an unusual localization for thyroid carcinomas in ectopic thyroid tissue. Thyroid carcinoma arising in ectopic thyroid tissue within a branchial cyst is extremely rare. Complete thyroidectomy may be necessary to eliminate an occult thyroid carcinoma.     

Lymphoepithelial cysts of the thyroid gland. A case report and review of the literature

We report a case of multiple lymphoepithelial cysts of the thyroid gland in a patient with severe chronic lymphocytic thyroiditis. Lymphoepithelial cysts of the thyroid gland are rare lesions that are histologically similar to branchial cleft cysts found in the lateral neck. The cysts have an epithelial lining that is usually stratified squamous epithelium but may be focally respiratory-type epithelium. Abundant lymphoid tissue is present beneath the epithelium, and lymphoid follicles with reactive germinal centers are common features in the walls of the cysts. Because of their similarity to branchial cleft cysts and the presence of intrathyroidal branchiae-derived structures such as thymus and parathyroid gland tissue in the vicinity of some cysts, lymphoepithelial cysts of the thyroid have been postulated to arise from remnants of branchial derivatives; origination from solid cell nest remnants of the ultimobranchial bodies has been raised as a possibility. A definitive origin, however, has not been established. An association with chronic thyroiditis has been noted in 8 of the previously reported 16 cases occurring in a background of Hashimoto or chronic lymphocytic thyroiditis.     

Thyroid papillary carcinoma arising in ectopic thyroid tissue within a branchial cleft cyst

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.     

Thyroglossal duct cyst cancer most likely arises from a thyroid gland remnant

Thyroglossal duct cancer is a rare entity, occurring in 1.5 % of all thyroglossal duct cysts (TDC). A definitive consensus about its neoplastic origin has not been established as two contrasting theories exist, one proposing an origin in extra-thyroid remnants and the other a metastatic localization of a primary thyroid cancer. We compare morphological and molecular characteristics of both thyroglossal and thyroid carcinomas in a case series from our institute. We evaluated histology of 80 TDC. In 12 cases, prior cytological evaluation had been performed by liquid-based cytology (LBC). The BRAF gene was examined for mutations, and the histology of both thyroglossal duct and synchronous thyroid carcinoma was reevaluated. In 9 out of 80 (11 %) TDC cases, a papillary thyroid cancer (PTC) was diagnosed. In five out of nine (56 %) thyroglossal carcinomas, a synchronous thyroid cancer was diagnosed: 3 PTC and 2 follicular variant PTC (FVPC). In five thyroglossal carcinomas, mutated BRAF (V600E) was found, three in PTC and in thyroglossal as well as in the synchronous tumor in the thyroid. All the patients are in a disease-free status and still alive. Our results suggest that the majority of thyroglossal carcinomas most likely develop as a primary malignancy from a thyroid remnant. Neither the presence of V600E BRAF mutations nor that of a well-differentiated thyroid carcinoma changed the outcome or disease-free survival. We suggest that a diagnosis of thyroglossal carcinoma should be followed by a detailed evaluation of the thyroid gland. In the absence of clinical and radiological thyroid alterations, follow-up as for thyroid cancer is the correct management.     

Primary papillary carcinoma of the thyroglossal duct cyst--a case report

Thyroglossal duct cyst is the most common developmental anomaly of the thyroid gland, presenting as a mid line neck swelling. Malignancy arising in them is a rare event, with papillary thyroid carcinoma being the commonest. Thyroglossal duct cyst carcinomas are usually asymptomatic and are not suspected preoperatively in most instances, hence the need for surgical excision and careful pathological examination of these cysts. We present a case of a 57 year old lady who underwent a Sistrunk procedure for the removal of thyroglossal duct cyst, which was responsible for a progressive mid line neck swelling of 2 months duration. The thyroid gland was normal. Histological examination of the excised cyst showed a papillary thyroid carcinoma arising in the thyroglossal duct cyst. Long term survival of patients with thyroglossal duct cyst carcinoma is excellent.     

Diagnosis of papillary carcinoma in a thyroglossal duct cyst by fine-needle aspiration biopsy

The incidence of papillary thyroid carcinoma arising in a thyroglossal duct cyst is rare and occurs in about 1 % of thyroglossal duct cysts. Only 17 such cases diagnosed with fine-needle aspiration biopsy have been previously reported in the English-language literature, with a diagnostic rate of 53%. In this article, the cytologic features of the current case are emphasized and those of the previous reported cases are briefly reviewed. Diagnostic pitfalls of papillary carcinoma arising in thyroglossal duct cysts diagnosed by fine-needle aspiration biopsy are also discussed.     

Papillary carcinoma arising in ectopic thyroid tissue within a branchial cyst.

The first case of a papillary carcinoma arising in ectopic thyroid tissue within a branchial cyst in a 34 yr old woman is presented. This also adds to the existing list of unusual sites where ectopic thyroid tissue has been described. All histological types of carcinoma have been reported in ectopic thyroid tissue, papillary carcinoma being the most common histological type, accounting for 85% of these tumors. The criteria for establishing this diagnosis of carcinoma arising in ectopic thyroid tissue within branchial cyst is discussed.     

Branchial cleft‐like cysts in Hashimoto's thyroiditis: A case report and literature review

We report an extremely rare case of branchial cleft‐like cysts in Hashimoto's thyroiditis. The patient was a 77‐year‐old man with a growing mass in the anterior neck. Ultrasonography and computed tomography revealed a cystic lesion with septum in the left thyroid and multiple small cystic lesions in the right thyroid. Lymph node swelling of the cervical region, supraclavicular fossa and submandibular region was also observed. Left thyroidectomy and lymph node dissection were performed. Histologically, cysts were lined by stratified squamous epithelium and dense lymphoid tissue having conspicuous follicle formation surrounded the epithelial lining. Solid cell nest (SCN)‐like aggregations were seen in the thyroid parenchyma adjacent to the cyst walls and a small number of thyroid follicles were observed in the fibrous wall. Immunohistochemically, it is suggested that both the cyst lining and SCN‐like aggregations are originally from thyroid follicles. Although, the exact histogenesis of branchial cleft‐like cysts remains unclear, there are probably two different processes for its development, one is of branchial cleft origin and the other is mere squamous metaplasia, while in our case the latter is suggested. Herein, we report our new case and update information about branchial cleft‐like cysts that appears in the literature.     

Diagnosis of necrotic and degenerate thyroid lesions: value of immunohistochemistry

Aims: Classification of necrotic or degenerate thyroid nodules can be difficult. The aim of this study was to investigate the value of cytokeratins, thyroid-specific markers (TTF-1 and thyroglobulin) and HBME-1 antibodies in such thyroid lesions. METHODS AND RESULTS: Twenty-eight necrotic or degenerate thyroid lesions, including four cervical cystic papillary carcinoma (CPC) metastases, were evaluated with immunohistochemistry for TTF-1, thyroglobulin, HBME-1, AE1&3, Cam5.2, MNF116 and cytokeratin (CK)19. There was loss of TTF-1 staining in all necrotic lesions, with positive staining in degenerate tumour cells of all four metastatic CPCs. Thyroglobulin was retained in 18 lesions. Dual CK19 and HBME-1 expression was seen only in six of seven necrotic papillary thyroid carcinomas and the four metastatic CPCs. Retained immunoreactivity for AE1&3 and Cam5.2 was seen in most necrotic papillary carcinomas (n = 11/11 and n = 10/11, respectively), poorly differentiated carcinomas (n = 2/3 and n = 3/3, respectively) and follicular-patterned areas of anaplastic carcinoma (n = 3/5 and n = 4/5, respectively). Cam5.2 showed spurious staining of macrophages in eight lesions. CONCLUSIONS: Thyroglobulin is useful in establishing the thyroid origin of a necrotic lesion. TTF-1 may be useful for highlighting degenerate tumour cells within metastatic CPCs. Retained expression of CK19 and HBME-1 is seen in necrotic papillary carcinomas. AE1&3 is the most specific and Cam5.2 the most sensitive of the CK cocktails in non-viable thyroid lesions.     

Papillary thyroid carcinoma of the thyroglossal duct cyst: comparative cytohistologic and immunochemical study of 2 new cases and review of the literature

We report a cytohistologic and immunohistochemical study of 2 cases of papillary thyroid carcinoma occurring in a thyroglossal duct cyst. The patients were a 21-year-old woman and a 48-year-old man. Needle aspiration cytology smears were consistent with papillary thyroid carcinoma. The Sistrunk procedure was done. Papillary carcinoma was found within a thyroglossal duct cyst. In 1 case, the tumor spread outside the cyst. Follow-up was uneventful in both patients (2 and 9 years, respectively). Our results would indicate that papillary carcinoma of thyroglossal duct cyst, though indistinguishable from its thyroid homologue, has a more indolent course and could therefore be singled out as a clinicopathologic entity. Needle aspiration cytology reliably assists in planning patient management.     

Thyroglossal duct carcinoma

Primary carcinoma of the thyroglossal duct is rare. This discussion reports two cases and reviews the 50 previously reported in the literature. The criteria for diagnosis include evidence of a thyroglossal duct remmant and a normal thyroid gland. The differentiation from cystic metastases to lymph nodes is pointed out. The histologic types parallel those of carcinoma of the thyroid gland, papillary carcinoma being the most common and having a generally favorable prognosis. The clinical presentation of these tumors is similar to that with benign cysts and thus is of limited value in the diagnosis.     

Multilocular lymphoepithelial cyst in the thyroid accompanied with a minute thyroid carcinoma

An aggregate (17 times 13 mm) of a few small cysts was incidentally found in the left lobe of the thyroid of a 42 year old man. The inner surface of the cysts was lined by stratified cuboidal to columnar epithelium, which showed occasional ciliation and keratinization. The cysts were densely surrounded by follicular lymphoid tissue. The lesion was designated as a multilocular lymphoepithelial cyst. Directly adjacent to the cyst-aggregate a minute focus of papillary thyroid carcinoma (6X6 mm) existed. Tubular or papillary clusters of cancer cells were occasionally contiguous to the lining epithelium, which had penetrated through the lymphoid mantle of the cysts. Histological features of the lesion in the thyroid suggested an origin of the cysts from the developmental rest of the branchial pouch; probably from the ultimobranchial body remnant.     

Pathology of Thyroglossal Duct: an Institutional Experience

Thyroglossal duct (TGD) is a developmental anomaly in which a remnant of the thyroid anlage is left in the neck during its descent from the foramen cecum of tongue to final pretracheal position. A persistent duct can lead to thyroglossal duct cyst (TGDC). Histologically, TGDC contains an epithelial lining of squamous or pseudostratified ciliated columnar epithelium and ectopic thyroid gland tissue in the duct wall. TGD-associated malignancy is rare, and the majority is papillary thyroid carcinoma (PTC). A total of 242 patients with a diagnosis of TGD-associated lesions were identified in our institute. Two hundred and seventeen cases were diagnosed as TGDC. Sixty-eight of 217 (31.3 %) cases of TGDC had ectopic thyroid tissue in the cystic wall. Thirty-nine cases had preoperative fine needle aspiration (FNA). Of these cases, 37 of 39 (94.9 %) demonstrated macrophages and 19 (48.7 %) also showed cells of squamous and/or columnar epithelial lining. Only two cases showed rare thyroid follicular cells. Thyroid carcinoma was identified in 18 of 242 (7.4 %) cases. All cases were diagnosed as PTC including 12 cases of classic PTC (66.7 %), 3 cases of follicular variant (16.7 %), 2 cases of tall cell variant (11.1 %), and 1 case of classic PTC with focal tall cell features (5.6 %). Nine cases had TGD component (either epithelial lining cysts or ectopic thyroid tissue). Ten patients also underwent total thyroidectomy (67 %). Of these patients, four had no tumor and one had an incidental medullary carcinoma. Five of 10 (50 %) cases had incidental PTC with a size range of 0.1–0.3 cm. Five patients had follow-up by imaging studies; no suspicious or nodular lesions were found in the thyroid. In conclusion, we report an institutional case cohort of 242 patients with TGD-associated lesions, including 217 TGDC and 18 cases of PTC. Only seven cases fulfilled the diagnostic criteria of TGD-associated PTC, i.e., the presence of components of TGD and a normal thyroid. In the remaining 11 cases, we could not differentiate with certainty between pyramidal primary thyroid PTC/Delphian node metastasis or TGD-associated PTC.