Prognostic implications of image cytometric assessments of nuclear DNA distribution pattern of neoplastic cells in thyroid medullary carcinoma. A retrospective study using disaggregated, formalin-fixed, paraffin-embedded specimens.

A modified technique for cytometric analysis of the nuclear DNA distribution pattern of neoplastic cells has been applied on archival histopathological specimens originating from 42 patients who had undergone thyroidectomy for medullary carcinoma of the thyroid gland. Five of the cases were of familial type. The DNA cytometric assessments were made by means of computerized image analysis techniques on Feulgen-stained, intact, cytodiagnostically identified neoplastic nuclei obtained from histopathologically selected areas of paraffin blocks. The nuclei were enriched by means of a cytospin technique after deparaffinization of pronase-induced disaggregation of 50 microns thick sections. Only seven of the tumours were found to consist of neoplastic cells where the nuclei showed a DNA distribution pattern of "aneuploid" type; six of these patients had a rapidly progressive neoplastic disease, but the seventh patient did not. Among all the patients whose tumour cell nuclei showed a cytometric DNA ploidy pattern of "euploid" type, not less than about half had a rapidly progressive neoplastic disease. Thus, even when a refined cytometric technique is used, the value of the nuclear DNA ploidy pattern of the neoplastic cells as a prognostic variable in MTC is limited.