DNA flow cytometric analysis of hemangiopericytoma

The biologic behavior of hemangiopericytoma is difficult to predict using clinical or histologic criteria. The authors studied 22 hemangiopericytomas (including "angioblastic meningiomas") from 16 patients. Included in the study were six recurrent tumors and one metastatic tumor. DNA flow cytometric analysis was performed on 21 tumors for which paraffin-embedded material was available. All of the tumors were DNA diploid. However, among patients with adequate follow-up information, all tumors that exhibited aggressive behavior (local recurrence, metastasis, death due to invasive disease) had S-phase fractions of greater than 9% and proliferative indices (S-phase plus G2M phase) of greater than 11%. There was also a trend toward aggressive behavior in tumors with necrotic foci. Tumors arising in the central nervous system behaved more aggressively than primary tumors at other sites. This study showed a trend toward more aggressive behavior in hemangiopericytomas with higher proliferative indices. DNA ploidy, however, was not a useful indicator of biologic behavior in these tumors.