Acute infarction of meningioma demonstrated by diffusion-weighted MR imaging

Excerpt

A seventy-seven year old woman presented with depression and worsening memory since 2 years. Contrast enhanced Head MRI revealed two large homogeneously enhancing extra-axial masses (Fig. 1)––the larger one bifrontal in location arising from the planum sphenoidale (arrow) and the smaller one from the left frontal convexity (arrowhead), without diffusion abnormality in the smaller mass on the diffusion weighted imaging (DWI) (Fig. 2a) and apparent diffusion coefficient (ADC) sequences (Fig. 2b). Non-contrast CT scan showed extensive calcifications in the left frontal mass, characteristic of meningioma (Fig. 3). Diagnostic conventional catheter angiogram (without embolization) was performed to assess the vascularity of the tumors as surgery was contemplated. The bifrontal mass was supplied by right anterior ethmoidal, right ophthalmic and left callosal artery and the left frontal mass was supplied by the left middle meningeal artery (Fig. 4). Presurgical planning limited MRI without diffusion sequences done a day after the conventional angiogram revealed development of heterogeneous enhancement in the left frontal smaller mass with central non-enhancing area (Fig. 5). The larger bifrontal mass was surgically excised and the histology was meningothelial meningioma WHO grade 1. Post-operative routine MRI revealed, in the smaller mass, hyperintense signal on DWI (Fig. 6a) and hypointense signal on ADC sequence (Fig. 6b) indicating restricted diffusion. Heterogeneous enhancement was similar to the preoperative MRI. This was limited to the tumor without involvement of the brain parenchyma. Hence, this represents acute infarction in the tumor. As the heterogeneous enhancement representing necrosis and infarction developed after the angiogram but before the surgery we believe that the infarction in the smaller mass is related to vasospasm or vascular occlusion of the feeding arteries that might have occurred during the diagnostic angiogram. Two days later, patient developed drug-induced thrombocytopenia and right hemiparesis, hemorrhage in the tumor as well as the adjacent brain parenchyma (which may be related to thrombocytopenia), cerebral edema and mass effect, demonstrated on Head CT scan. As the patient developed systemic complications and was transferred to a rehabilitation center, no further intervention or imaging was performed. Infarction in a meningioma is quite uncommon. To our knowledge, this is the first case of acute infarction in meningioma demonstrated on DWI. Diffusion weighted imaging has an important role not only in the diagnosis of acute parenchymal infarction of brain but also acute tumoral infarction as in this case and may have a role in assessing response to therapeutic embolization of tumors.

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