PROLIFERATIVE ACTIVITIES IN CONVENTIONAL CHORDOMA - A CLINICOPATHOLOGICAL, DNA FLOW CYTOMETRIC, AND IMMUNOHISTOCHEMICAL ANALYSIS OF 17 SPECIMENS WITH SPECIAL REFERENCE TO ANAPLASTIC CHORDOMA SHOWING A DIFFUSE PROLIFERATION AND NUCLEAR ATYPIA

Chordoma shows various degrees of atypia histologically, however, the relationship between the histological features and the biological beha vior still remains controversial. The authors subclassified 17 specime ns with chordoma into two groups (ie, trabecular type showing a trabec ular pattern and solid type mainly consisting of a diffuse proliferati on of tumor cells). The histological grading was performed according t o the degree of nuclear atypia on a scale of 1 to 3. Using DNA flow cy tometric and immunohistochemical techniques, both the proliferative in dex (% S + G(2) + M phase) and the MIB-1 labeling index (LI) of the tu mor cells were estimated regarding their proliferative activities. In addition, p53 overexpression was also investigated using immunohistoch emical techniques. There were eight (47.1%) specimens of trabecular ty pe and nine (52.9%) of solid type. In nine specimens of solid type, th ose with higher nuclear atypia (grade 2 or 3) were significantly more frequent (five specimens, 55.6%) than in trabecular type in which all of the eight specimens were grade 1 (P = .044). The proliferative inde x was significantly higher in grade 2 or 3 lesions than in grade I les ions (P = .014), and the MIB-1 LI tended to be higher in solid type th an in trabecular type (P = .088). p53 overexpression was detected in t wo specimens of solid type, and the MIB-1 LI in these two specimens wa s significantly higher (P = .037) than that in the specimens without p 53 overexpression. It was considered that the preceding anaplastic his tological features, including either diffuse proliferation or high gra de nuclear atypia, together with p53 overexpression, were thus closely related to the proliferative activities in chordomas. (C) 1996 by W.B . Saunders Company