1982 Volume 24 Issue 2 Pages 466-495
The nuclear DNA content of a tumor cell was determined by Feulgen cytofluorometry in 30 patients with pleomorphic adenoma to study the correlations between the nuclear DNA content and the histological types of the tumor, cellular atypia or clinical malignancy. Moreover, since a tumor histopathologically shows various aspects of proliferative changes, the histological patterns in the same tumor were also investigated using nuclear DNA content as an index. Tissue sections (10μ) were used for investigation by histological patterns.
From the results, the following were considered:
1) Appearance of polyploid is the key factor for differentiating the patients with pleomorphic adenoma from those with potentiality of malignancy. The reason why proliferation of the pleomorphic adenoma is slow seems to be that the cells at G1 phase are predominant and the cells at S, G2, or M phase are very few.
2) Proliferation ability is more increased in the salivary-duct-derived epithelial tumor cells than in the myxoid areas (which involves myoipithelium), the chondroid areas, and the myoma-like areas.
3) Semi-malignant pleomorphic adenoma and malignant pleomorphic adenoma are characterized by a shift of the major mode to 3c or disappearance of a stem line, appearance of polyploid over 5 % and an increase in the number of cells at S, G2, or M phase along with a decrease in cells at G1 phase. Therefore, even in pleomorphic adenoma with clinically benign findings, the appearance of polyploid or an increase in the cells at S, G2, or M phase (especially when the rate exceeds 50 %) seem to suggest a possibility of malignancy.
