The status of MGMT protein expression is a prognostic factor for meningeal hemangiopericytoma: a clinicopathologic and immunohistochemical study of 12 cases at a single institution

Meningeal hemangiopericytoma (HPC) is a clinicopathologically well-characterized malignancy with a high tendency to recur locally and to metastasize outside the central nervous system (CNS). We render clinicopathologic features of 12 cases of this uncommon tumor to further elucidate the relationship between the status of the DNA-repair enzyme O-6-methylguanine-DNA methyltransferase (MGMT) and the prognosis. Twenty-five specimens of meningeal HPC belonging to 12 patients were obtained at a single institution from 1992 to 2001. Correlations of histologic parameters, immunohistochemical study and clinical features were assessed. This series included five men and seven women with a median age of 37.5 years at the first surgery. The median post-operative follow-up period was 7.6 years. Six patients (55%) had single or multiple local tumor recurrences. The mean time to recurrence was 6.7 years. Distant metastasis occurred in three patients (27%) at a mean time of 6.5 years after first operation. The most frequent metastatic sites were liver and lung. Histopathologically, eight primary tumors (67%) belonged to WHO grade II, while four primary tumors (33%) belonged to WHO grade III. Immunohistochemically, 18% primary tumors exhibited 3+ to 4+ nuclear staining for MGMT protein, 18% exhibited 2+ staining, and 64% exhibited 0 to 1+ staining. The overall survival rate was 67 and 33% for primary tumors with 0 to 1+ and 2+ to 4+ MGMT staining, respectively (P = 0.018). The study illustrates aggressive behavior of meningeal HPC and the prognostic value of the status of MGMT protein expression.