Drainage post-thyroglossal duct remnant surgery: possible source and analysis.

OBJECTIVE: To establish the distance between tongue base salivary tissue and hyoid. Also, to identify protein differences between thyroglossal duct (TGD) remnants and salivary tissue in order to distinguish drainage source post Sistrunk surgery. METHODS/SETTING: The anterior neck block was obtained from 10 adult cadavers with no known neck pathology. The distance between the normal salivary tissue and hyoid was measured histologically. Immunohistochemistry (IHC) was then performed on 20 archived tissue blocks from pediatric patients post Sistrunk surgery to identify the presence of amylase, MUC5AC (tracheobronchial mucin), and MUC7 (salivary mucin) within the excised specimen. RESULTS: Average distance between salivary tissue and the hyoid within adult human cadavers was 3.3 mm (range, 1.0-4.2 mm). IHC revealed all excised TGD remnants contained amylase and MUC5AC but none contained MUC7. Both amylase and MUC7 were present within adjacent salivary tissues. CONCLUSIONS: Salivary tissue of the tongue base normally resides an average of 3.3 mm from the hyoid within the adult population. Biochemical analysis showed MUC5AC was specific for TGD remnants while MUC7 was specific for salivary tissue. Amylase does not distinguish between the two tissues.

Thyroid transcription factor 1 expression in cystic lesions of the neck: an immunohistochemical investigation of thyroglossal duct cysts, branchial cleft cysts and metastatic papillary thyroid cancer.

Cervical metastases of papillary thyroid cancer (PTC) are of particular diagnostic importance, because they can mimic branchiogenic cysts clinically and histopathologically when undergoing cystic change. Immunohistochemical stains for thyroid transcription factor 1 (TTF-1), which are positive in thyroid cancers, are reported to be valuable in establishing diagnosis. However, TTF-1 may also be expressed in dysontogenetic cysts of the neck. Therefore, immunohistochemical stains for TTF-1 and thyroglobulin (TG) were performed on each of the ten thyroglossal duct cysts, branchial cleft cyst and lymph node metastasis of PTC. Five in ten cases of thyroglossal duct cysts were positive for TTF-1, but all were negative for TG. One of the ten branchial cleft cysts stained for TTF-1, while all cases were negative for TG. All ten cases of lymph node metastases of PTC showed positive for TTF-1, nine of which were positive for TG. Since a positive immunostaining for TTF-1 in cystic lesions of the neck was not only found in metastases of PTC, but also in non-malignant branchiogenic cysts, additional investigations, e.g. an immunostaining for TG, should be added in difficult cases.

Papillary carcinoma arising in thyroglossal duct cyst in the lateral neck.

The patient presented here, a 74-year-old female, had a 3-year history of a gradually enlarging painless nodule in the right submental lateral region of the neck. A neck CT scan showed a well-demarcated cystic lesion, measuring 25mm in diameter, but without any definite evidence of neoplastic foci in the lymph nodes, thyroid gland, or lung. Clinicians first interpreted it as branchial cleft cyst, and a cystectomy was performed. Gross examination revealed a unilocular cystic lesion filled with yellowish clear fluids, containing a markedly thinned fibrous wall with smooth inner surface, partly coexisting with tiny solid and papillary-like components. On microscopic examination, the cystic tumor was lined by mono-layered ciliated columnar or metaplastic stratified squamous epithelium with underlying ectopic thyroid follicles or lymphocytic infiltrate, reminiscent of thyroglossal duct cyst (TDC), partly adjacent to the compressed lymph node tissue. Its solid parts were composed of a proliferation of atypical cuboidal to columnar epithelial cells with occasional nuclear grooves or intranuclear inclusions, arranged in a papillary growth pattern with supporting delicate fibrovascular cores. Immunohistochemically, these atypical cells were positive for thyroid transcription factor 1, thyroglobulin, and cytokeratin 19. Therefore, we finally made a diagnosis of papillary carcinoma (PC) arising in TDC in the lateral neck. Although metastatic thyroid PC of cervical lymph node was an important differential diagnosis owing to various overlapping clinicopathological features, coexistent benign lining epithelium or thyroid follicles, a histological hallmark of TDC, were present in the current case.

Immunoglobulin A defines secretions from salivary tissue in post-Sistrunk procedure drainage.

OBJECTIVES: This was a pilot study to establish a protein difference between thyroglossal duct cyst fluid relative to oral saliva, in order to differentiate patients with residual thyroglossal cyst from those with salivary fistula in the case of post-Sistrunk procedure incisional drainage. Past immunohistochemistry studies on archived tissue blocks from post-Sistrunk procedure patients have shown MUC5AC to have elevated concentrations in thyroglossal duct relative to salivary tissue; secretory immunoglobulin A (IgA) was also chosen as a candidate protein based on previously published reports of its increased concentration in saliva relative to respiratory secretions. DESIGN: Diagnostic tests were assessed. Thyroglossal duct cyst fluid and oral saliva were obtained from 12 patients. Enzyme-linked immunosorbent assay (ELISA) was then performed on the samples to identify the presence of MUC5AC and IgA. SETTING: Tertiary care hospital. SUBJECTS: Patient fluid samples were taken immediately postoperatively for patients undergoing Sistrunk procedure at one institution. Presence of thyroglossal duct cyst was confirmed in all cases by pathology. RESULTS: Seven of 12 thyroglossal duct cyst fluid samples were shown to have elevated absorbance with ELISA for MUC5AC. In experiments for IgA, 10 of the 12 saliva samples had elevated absorbance compared with thyroglossal duct fluid samples obtained from the same patient. CONCLUSIONS: IgA is an accurate identifier of saliva compared with thyroglossal duct fluid in secreted samples obtained from the same patient.

Expression of thyroid transcription factor 1 (TTF-1) in extra thyroidal sites: papillary thyroid carcinoma of branchial cleft cysts and thyroglossal duct cysts and struma ovarii.

The thyroid-associated transcription factor-1 (TTF-1) is a nuclear tissue specific protein, found only in thyroid and thyroid tumors regardless of histologic type as well as in lung carcinomas. Most ectopic thyroid tissue are found along the thyroglossal duct tract and around the bilateral main lobes of thyroid glands. Ectopic thyroid tissue within a branchial cleft cyst is a rare abnormality and papillary carcinoma arising in this tissue is extremely rare. Thyroid tissue may also be found as one of the many components of teratoma, particularly those located in the ovary. The aim of this study is to evaluate, through immunohistochemistry, the expression of TTF-1 in branchial cleft cysts with ectopic normal thyroid tissue, in primary thyroid papillary carcinomas of branchial cleft cysts and thyroglossal duct cysts and in struma ovarii, in order to evaluate the expression of this antigen in extra thyroidal sites.

Cyst fluid levels of carcinoembryonic antigen, carbohydrate antigen 19-9, squamous cell carcinoma antigen, and amylase in thyroglossal duct and branchial cleft cysts.

Cyst fluid was aspirated from five thyroglossal duct cysts (TDCs) and four branchial cleft cysts (BCCs). The cyst fluid levels of carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 19-9, squamous cell carcinoma antigen (SCC), and amylase were measured and compared between the two types of cyst. The enzyme immunoassay technique was used for CEA and CA19-9, while SCC and amylase levels were measured by the immunoradiometric assay and nitrophenol method, respectively. Immunostaining for CEA, CA19-9, and amylase was also performed. The serum levels of these markers in both groups of patients were within the normal ranges. In contrast, their cyst fluid levels were extremely high. There was no significant difference in the cyst fluid levels of CEA and SCC between the two types of cyst; however, the cyst fluid from the TDCs showed significantly higher levels of CA19-9 and significantly lower levels of amylase compared with that from the BCCs. Immunostaining revealed expression of CA 19-9 in nearly half the columnar epithelial cells in the TDCs, but not in the squamous epithelial cells in the BCCs. CEA and amylase were not found in the epithelial cells of either type of cyst. These findings seem to reflect the difference in etiology between TDCs and BCCs.

Spatial correlation between thyroid epithelial cells expressing class II MHC molecules and interferon-gamma-containing lymphocytes in human thyroid autoimmune disease.

In this immunohistochemical study we addressed the question whether aberrant class II MHC expression by thyroid epithelial cells (thyrocytes) in established thyroid autoimmune disease is the result of release of interferon-gamma (IFN-gamma) by adjacent lymphocytes. Thyroids from eight cases of Hashimoto's thyroiditis, 13 cases of Graves' disease and 10 cases of focal thyroiditis were studied. Both thyrocytes expressing class II MHC and lymphocytes containing immunoreactive IFN-gamma were found in all 31 autoimmune thyroids. In a serial section study of these thyroids, IFN-gamma-expressing lymphocytes were found within 50 microns of class II MHC-positive thyrocytes in 89% of 282 randomly selected fields. Conversely, class II MHC-positive thyrocytes were found within 50 micron of aggregates of IFN-gamma-positive lymphocytes in 82% of 272 randomly selected fields. These findings support the view that in established thyroid autoimmune disease expression of class II MHC by thyrocytes is the result of local release of IFN-gamma.