The utility of some modern techniques in understanding thyroid pathology

Recent advances in cytometry, cytogenetics and molecular genetics of thyroid tumours and tumour-like lesions

In this review we summarize the most recent advances of flow and image cytometry, cytogenetics and molecular genetics of tumours and tumour-like lesions of the thyroid, especially focusing on the putative relationship between nodular goitres and adenomas, the differential diagnosis of benign and malignant neoplasms and the pathogenesis and prognosis of carcinomas. Data obtained by in situ hybridization and immunohistochemical detection of proliferative markers, metal binding proteins and oncogenes, anti-oncogenes, growth factors and growth factor receptors are also used whenever appropriate.

Immunohistochemical localization of metal binding proteins in thyroid tissues and tumors

Positive immunohistochemical staining for three metal binding proteins, ceruloplasmin, lactoferrin, and transferrin, has been suggested to be a reliable diagnostic marker of malignant but not benign thyroid neoplasms. We tested this hypothesis on a series of 9 nodular hyperplasias, 17 follicular adenomas, 54 papillary carcinomas, 20 follicular carcinomas, and 3 anaplastic carcinomas of thyroid using formalin-fixed paraffin-embedded tissues. We found focal staining for ceruloplasmin and lactoferrin in approximately 25% of follicular adenomas examined; focal ceruloplasmin positivity was also seen in nonneoplastic tissues surrounding thyroid neoplasms. No staining for these markers was found in malignant neoplasms or hyperplasias. Transferrin was found in 55% of papillary carcinomas, but more follicular adenomas (20%) than follicular carcinomas (11%) were positive using this antiserum. These findings show that immunostaining for these antigens is not a reliable method to distinguish benign from malignant thyroid lesions of follicular cell origin.

The study of endocrine tumors by flow and image cytometry

Both DNA flow and image cytometry are methods that can be used for the quantitative determination of cellular DNA content. Objective, quantitative analysis of cellular morphology can also be obtained using image cytometry. Data thus generated have been shown to be of diagnostic and prognostic use in the study of many solid tumors and would be of particular value in the evaluation of endocrine tumors that show a poor correlation between their histology and biological behavior. The main application of these techniques to endocrine tumors has been in the analysis of thyroid nodules, although a limited number of studies of parathyroid, pituitary, adrenal, and pancreatic neuroendocrine tumors and tumors of the dispersed neuroendocrine system have been reported. Review of these studies shows that in the endocrine organs DNA and morphometric measurements have a very limited role in the diagnosis of individual cases, but are important as prognostic variables. The high incidence of abnormal DNA content in histologically benign lesions of the endocrine glands has important biological implications. Further investigation of this phenomenon may help to elucidate the process of endocrine tumorigenesis.