Thyroid lesions

Taylor GN, Lloyd RD, Bruenger FW, et al. 1993a. 241 Am-induced thyroid lesions in the beagle. Health Phys 64(6) 65 3-660. 

Other Systemic Effects. Mild nonspecific endocrine lesions were observed after inhalation exposure to 1,2-dibromoethane. After subchronic exposure to 75 ppm, rats had adrenal lesions consisting of swelling and/or cytoplasmic vacuolization of cells in the zona fasciculata of the cortex and thyroid lesions consisting of slight decreases in follicular size. Degenerative changes in the adrenal cortex occurred at elevated incidence in female Fischer 344 rats after chronic exposure to 40 ppm... 

Toxaphene caused a dose-related increase of hepatocellular carcinomas in mice fed 98 or 198 ppm for 80 weeks. In rats, there was a significantly increased incidence of neoplastic thyroid lesions at the high dose." The lARC has determined that there is sufficient evidence in experimental animals for the carcinogenicity of toxaphene and that it is possibly carcinogenic to humans. ... 

Kashima, K., Yokoyama, S., Daa, T., Nakayama, I., Nickerson, P. A., and Noguchi, S. 1997. Cytoplasmic biotin-like activity interferes with immunohistochemical analysis of thyroid lesions A comparison of antigen retrieval methods. Mod. Pathol. 70 515-519. 

Collins et al. (1977) conducted one of the more comprehensive evaluations of the histopathology of intermediate-duration exposures to Aroclor 1254 in rats. Rats were fed 5, 50, or 500 ppm Aroclor 1254 in food for 4 weeks (approximately 0.44,4.4, or 44 mg/kg/day). Ultrastructural changes in the thyroid were evident at the lowest exposure level and became more pronounced and evident with light microscopy at the 50 ppm exposure level (4.4 mg/kg/day). Serum concentrations of TT4 were significantly depressed (42%) at the 50 ppm level and both TT4 and TT3 were depressed (79 and 13%, respectively) at the 500 ppm level. Thyroid lesions in rats that were exposed to 500 ppm for 6 weeks followed by 250 ppm for 6 weeks were largely absent after a subsequent 12 weeks on a control diet, suggesting substantial recovery, and were not evident at all after a period of 35 weeks on the control diet (Collins and Capen 1980a). A similar time course of recovery of serum TT4 concentrations was observed. Thus, the observed lesions in this study and at these doses appeared to be reversible. 

Marker Expression in Benig n and Maiignant Thyroid Lesions ... 

TGB, TTF-1, and TTF-2 are present in benign thyroid lesions and in more than 95% of differentiated thyroid carcinomas. 

Komminoth P, Roth J, Saremaslani P, et al. Polysialic acid of the neural cell adhesion molecule in the human thyroid A marker for medullary thyroid carcinoma and primary C-cell hyperplasia An immunohistochemical study on 79 thyroid lesions. Am Surg Pathol. 1994 18 399-411. 

Miettinen M, Kovatich AJ, Karkkainen P. Keratin subsets in papillary and follicular thyroid lesions A paraffin section analysis with diagnostic implications. Virchows Arch. 1997 431 407-413. 

Bartolazzi A, Gasbarri A, Papotti M, et al. Application of an im-munodiagnostic method for improving pre-operative diagnosis of nodular thyroid lesions. Lancet. 2001 357 1644-1650. 

Ostrowski ML, Brown RW, Wheeler TM, et al. Leu 7 immunote-activity in cytologic specimens of thyroid lesions with an emphasis on folliculat neoplasms. Diagn Cytopathol. 1995 12 297-302. 

We evaluated the ERP/PRP content in thyroid tumors (V4) and the ERP/PRP was conelated in 135 patients. There was no statistical association among receptor content, age, sex, tumor size, and classification. Metastases at presentation, seen in 50% of the patients, were unrelated to receptor content. While ERP/PRP are detectable commonly in thyroid lesions, no clear relationship to these clinical and prognostic features was found. 

Casey MB, Zhang S, Jin L, Kajita S, Lloyd RV. Expression of cyclooxygenase-2 and thromboxane synthase in non-neoplastic and neoplastic thyroid lesions. Endocr Pathol. 15 (2004) 107-116. 

Note-. Ultrasonography, including color flow measurements (Doppler method), is a valuable tool in the differential diagnosis of benign and malignant thyroid lesions. 

In hypofunctional nodules, discrimination between rare malignant and frequent benign thyroid lesions is a major challenge. 

Despite few controversial studies reporting the detection of RET/PTC rearrangements in benign or non-papillaty thyroid lesions such as Hashimoto thyroiditis, follicular and Hiirthel cell adenoma, the RET rearrangements seems to be characteristic for papillary thyroid carcinoma and not reported in any other thyroid carcinoma. The reported positive results in other thyroid lesion are possibly due to the presence of microfocus of papillary microcarcinoma, latent carcinoma or atypical follicular cells in transformation. 

Table 4. Key neoplastic and non-neoplastic thyroid lesions in the 2-year carcinogenicity study of sodium chlorate in F344/N rats ...

In chronic toxicity, the clinical manifestations are pulmonary syndrome, skin syndrome, allergy, gastrointestinal irritations, nausea, cardiomyopathy, hematological disorders, and thyroid lesion. 

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