The significance of nuclear diameter in the biologic behavior of thyroid carcinomas: a retrospective study of 127 cases.

The relationship between nuclear diameter and biologic behavior was studied in 127 cases of thyroid carcinoma. Using a sonic digitizer coupled to a minicomputer, nuclear diameters of 200 randomly selected cancer cells from each case (hematoxylineosin-stained paraffin sections) projected at X 400 magnification were traced and averaged. A total of 25,400 measurements were made. The nuclear diameters varied from 4.7 to 13.1 micron. By analysis of variance, the nuclear diameters were significantly different (p = 0.0007) among the four types of thyroid cancers, being largest in the undifferentiated cancers (8.7 +/- 0.8 micron) and smallest in the medullary cancers (6.6 +/- 0.1 micron). Nuclear diameter was also significantly correlated with degree of tumor differentiation (p = 0.002), maximal tumor diameter (p = 0.03), mitotic rate (p = 0.002), and 5-year survival (p less than 0.05) for all types of tumors. The correlation between nuclear diameter and disease stage was significant only for undifferentiated cancers (p = 0.04). No significant correlations were seen between nuclear diameter and duration of disease, sex, or age of the patient.