Abstract
Meningioangiomatosis is a rare hamartomatous lesion or meningiovascular malformation in brain. In extremely rare condition, meningioma may occur together with meningioangiomatosis, and only 19 cases have been described in English literature until now. We now report a case of meningioangiomatosis-associated meningioma with atypical and clear cell variant. A 34-year-old man presented a 3-month history of progressive numbness and weakness of his left lower extremity. He had no stigmata of neurofibromatosis type 2. Magnetic resonance imaging (MRI) revealed multifocal lesions in the right frontoparietal lobe. The lesions were totally removed. Microscopically, parts of lesions were atypical and clear cell meningioma corresponding to WHO grade II. The adjacent brain parenchyma showed the histological features of meningioangiomatosis. Neoplastic cells in atypical meningioma area were immunoreactive to epithelial membrane antigen (EMA) with high MIB-1 index of up to 20%. However, the spindle cells in meningioangiomatosis area were negative for EMA with low MIB-1 index of up to 1%. The diagnosis of atypical meningioma associated with sporadic meningioangiomatosis was made. To our knowledge, this is the first case of a meningioangiomatosis-associated meningioma with atypical and clear cell variant component to be described. The patient had been followed-up for 11 months without adjuvant radiotherapy or chemotherapy. No tumor recurrence was found during this period. Meningioangiomatosis-associated meningioma is more likely to occur in younger patients and histologically to mimic parenchymal invasion of brain. We suggest that postoperative radiotherapy or chemotherapy should be given careful consideration to avoid over-treatment due to erroneously interpret as malignant meningioma.
Highlights
Meningioangiomatosis is a rare meningiovascular malformation in the central nervous system, which is characterized by a plaque-like or nodular mass within the cerebral cortex and overlying leptomeninges in the patients with intractable seizures
We found the MIB-1 index was consistently higher in the meningioma component rather than meningioangiomatosis component, and there were lack of epithelial membrane antigen (EMA)-positive cells in the proliferative perivascular areas in meningioangiomatosis component
Meningioma components of the lesion mixed atypical cells and clear cells with hypercellularity, higher mitotic activity and higher MIB-1 index which corresponded to WHO grade II; the fibroblast-like spindle cells disposed around the blood vessels were bland appearance with lower proliferation index and lacking EMA expression
Summary
Meningioangiomatosis is a rare meningiovascular malformation in the central nervous system, which is characterized by a plaque-like or nodular mass within the cerebral cortex and overlying leptomeninges in the patients with intractable seizures. There was only up to 1% of MIB-1 index in perivascular spindle cells (Figure 4c and 4d) Based on these findings, a histological diagnosis of atypical meningioma (WHO grade II) associated with meningioangiomatosis was made. Meningioma components of the lesion mixed atypical cells and clear cells with hypercellularity, higher mitotic activity and higher MIB-1 index which corresponded to WHO grade II; the fibroblast-like spindle cells disposed around the blood vessels were bland appearance with lower proliferation index and lacking EMA expression. The lesion as the brain invasion by atypical or clear cell meningioma because high level of MIB-1 index is known to be detected in meningiomas of brain invasion [23] These findings suggest encircled gliotic cortical tissue is not true invasion but a condition simulated by meningioangiomatosis. Further investigation with more cases and longer follow-up data need to be performed to clarify whether or not aggressive variant of meningioma might result in a worse prognosis of meningioangiomatosis-associated meningioma
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