Abstract
Thymomas are the most common anterior mediastinal tumors. The clinical course of patients with thymomas varies widely despite their histologically benign appearance. Treatment decisions are based on local invasion. To determine the degree of malignancy among thymomas, thymomas were examined by DNA microphotometry. The DNA histograms were analysed for ploidy pattern and histogram pattern (by Asamuraet al.) . W e tried to decide adjuvant therapy from DNA histograms. Normal thymuses and two of the thymomas were DNA diploid whereas ten thymomas were aneuploid. There was no relationship between the ploidy pattern and the clinical stage of the thymomas. Normal thymuses and three of the thymomas were of Histogram pattern I, and nine thymomas were of pattern II . Histogram pattern II was seen in 50 % of the noninvasive thymomas, and in 88 % of the invasive thymomas. One case of a noninvasive thymoma recurring after surgery revealed Histogram pattern II. Histogram patterns may be useful in making decisions for adjuvant therapy.
