Determination of malignancy of cartilaginous tumors (2). Determination of malignancy by nuclear DNA contents and their distribution patterns in cartilaginous tumors

: In 40 different types of cartilaginous tumors, the number of binuclear cells was calculated and DNA content was examined using fluorescent Feulgen cytophotometric technique. In 7 enchondromas and 1 synovial chondromatosis, the DNA content was diploid in 7 and hypotetraploid in 1, and showed a unimodal normal distribution. The number of binuclear cells was 0.1-0.45%, and the mean DNA content was below 4. These cases showed no evidence of disease after curettage and bone graft. The follow-up period was from 4 years 6 months to 7 years 1 month, averaging 6 years 2 months. In 2 enchondromatoses and 2 benign chondroblastomas, the DNA content was diploid and showed a unimodal normal distribution. One chondromyxoid fibroma showed a broad-unimodal tetraploid distribution, and one benign chondroblastoma showed a broad-aneuploid distribution. The nuclear DNA content was sometimes histologically similar to that of chondrosarcoma in some benign cartilaginous tumors. In 5 secondary chondrosarcomas, the DNA content was hypo- or hypertetraploid, hexaploid, and showed broad-unimodal or broad-bimodal distribution. The number of binuclear cells was from 13% to 23%. Although the size of the nucleus was small, the number of binuclear cells was evidently numerous. The preferred treatment for secondary chondrosarcoma is principally wide resection, but amputation is sometimes indicated in cases of recurrence and large tumor size. The follow-up period was from 2 years 2 months to 18 years 11 months, averaging 9 years 11 months. All 5 patients were surviving at the time of follow-up. The DNA content in chondrosarcoma was mostly hypo- or hypertetraploid, hexaploid, or octaploid and showed broad-unimodal, broad-bimodal or broad-aneuploid distribution. The number of binuclear cells was 0.55-3.5%. The mean DNA content was proportional to the number of binuclear cells, the positive correlation between the mean DNA content and the number of binuclear cells was found (p less than 1%).