Clinicopathological characteristics, hormone receptor status and matrix metallo-proteinase-9 (MMP-9) immunohistochemical expression in spinal meningiomas.

Meningiomas involving the spinal meninges show a reduced tendency to recur compared to those of the intracranial compartment. Nonetheless, due to the few reports with a significant number of patients, their biological characteristics largely remain to be investigated. With the aim of clarifying the biology of these tumors, we examined in the present paper the clinicopathological features, the estrogen receptor (ER) and progesterone receptor (PR) status, as well as the Ki-67 labeling index (LI) and matrix metallo-proteinase-9 (MMP-9) expression of 58 spinal meningiomas. Ki-67 LI ranged between 1% and 5% (median: 1%); no expression of ER was found in all the cases, whereas PR immunoexpression was found in 86% of the tumors. High MMP-9 expression was encountered in 46% of meningiomas, and it was significantly correlated with the percentage of PR expression. The recurrence rate was 1.7%. The only recurred case showed high MMP-9 expression, absence of PR and low Ki-67 LI. Our findings confirm that spinal meningiomas are indolent tumors with low growth fraction and recurrence rate. In these neoplasms, high MMP-9 expression seems to be associated with the development of recurrences only in the absence of PR expression. Thus, the evaluation of both MMP-9 and PR expression might be of use in the identification of spinal meningiomas at higher risk of relapse.