Endocrine Abstracts

Background: An increased incidence of thyroid cancer among young population of contaminated territories of Russia after Chernobyl accident made very important morphological verification of diagnosis. Many epidemiological and molecular studies of post-Chernobyl thyroid cancer conducted by various research teams required an independent review of tumour histology. The International Pathology Panel formed consensus diagnosis for each case of post-Chernobyl thyroid tumours and proposed an appropriate algorithm of morphological diagnosis (E.D.Williams et al., 2000). The main diagnostic problem arose for estimation of malignancy in some encapsulated follicular thyroid tumours. Doubtful features of tumour capsular invasion and focal morphological nuclear changes in tumour cells could be a reason to distinguish among benign thyroid tumours a group of borderline lesions or tumours of uncertain malignant potential. This classification group is not widely accepted, as the malignancy of encapsulated follicular thyroid tumours should be more precisely determined.

Aim: To analyse diagnostic and prognostic significance of immunoexpression of markers of malignancy in encapsulated thyroid tumours.

Material and methods: We studied an immunoexpression of markers of malignancy: Galectin-3, Cytokeratin-19, HBME-1, Fibronectin and Cyclin D1 in 51 benign, 87 malignant and 53 tumours of uncertain malignant potential.

Results: We revealed that 3.9% benign and 41.5% tumours of uncertain malignant potential express the markers of malignancy with a level of diagnostic specificity of 98–100%. Follow up during the period of 1–10 years after surgical thyroid lobectomy for borderline tumours showed no progression of tumour growth.

Conclusion: We concluded that some of benign and borderline thyroid tumours are represent malignant neoplasms with low grade and favourite prognosis.

Acknowledgments: The authors gratefully acknowledge the confirmation of diagnosis provided by the International Pathology Panel of the Chernobyl Tissue Bank: Professors T.I.Bogdanova, G.Fadda, G.Hunt, M.Ito, V.LiVolsi, J.Rosai, E.D.Williams.