Different responses of benign and atypical meningiomas to gamma-knife radiosurgery: report of two cases with immunohistochemical analysis

Abstract

Recent reports have shown that gamma-knife radiosurgery provides a safe and effective strategy for the management of brain tumors. To evaluate the role of stereotactic radiosurgery in the management of meningiomas, we investigated the histopathology of two patients. The patients, a 37-year-old man and a 54-year-old woman, presented with visual field disturbance or headache. Imaging studies demonstrated intracranial meningiomas--tentorial and sphenoid ridge, respectively. Each patient undewent subtotal surgical resection (more than 90% in both patients), followed by gamma-knife radiosurgery of the remnant tumor marginal doses of 15 Gy. Pathological examination of the original tumors revealed a meningothelial meningioma and an atypical meningioma, respectively. Enlargement of the remnant tumors 4 months after radiosurgery resulted in total surgical resection in both patients. Thirteen months later, the patient with the atypical meningioma underwent a third operation for early recurrence of the tumor. Histopathology was investigated, and MIB-1, p53, and bcl-2 labeling indexes (LI) were analyzed immunohistochemically. Histopathologically, the specimens showed necrosis and intratumoral vessel obliteration after radiosurgery in both cases. However, more remnant tumor cells survived in the atypical meningioma. Immunohistochemically, increased wild-type p53, decreased bcl-2 expression, and decreased MIB-1 LI were observed in the benign meningioma. In the atypical meningioma, on the contrary, MIB-1 LI was decreased and mutant-type p53 and bcl-2 expression were unchanged. The specimen from the third operation revealed an anaplastic meningioma, and MIB-1 LI was markedly increased. These findings suggest that the efficacy of radiosurgery may differ between benign and atypical meningiomas.

Predict Treatment Response by Magnetic Resonance Diffusion Weighted Imaging: A Preliminary Study on 46 Meningiomas Treated with Proton-Therapy

“…Indeed, high cell proliferation may lead to a higher cell density and, as a result, less stroma, both of which may cause more diffusion-restriction of water molecules, leading to lower ADC [ 31 ]. Thus, the different pre-treatment and longitudinal rADCm changes we found among groups supported the evidence that different subtypes of MN present different sensitivity to PT [ 25 , 32 ].…”

Risk Factors for Regrowth of Intracranial Meningiomas after Gamma Knife Radiosurgery: Importance of the Histopathological Grade and MIB-1 Index

“…Factors associated with better results of radiosurgery for nonbenign meningiomas include histopathological grade II [3,14] , absence of malignant progression [14] , and, possibly, expression of the wild-type of p53 protein [10] . A favorable infl uence of smaller target volume, initiation of treatment before radiological evidence of the tumor progression, and younger patient age on the outcome was also marked previously [9,11] , but was not confi rmed in the present study.…”

Contemporary Management of Meningiomas with Radiosurgery

“…In this context, given the probability of differential responses to radiosurgery for meningiomas with different WHO grades, delivery of higher radiosurgery doses may be considered for achieving improved local control for WHO grade II-III meningiomas [103,114].…”