T1 sagittal post gad T1 axial post gad T2 axial

Diagnosis: Grade 4 gliosarcoma.

Gliosarcoma is a rare glial neoplasm with sarcomatous dedifferentiation usually presenting in older patients which may contain cartilaginous and osseous elements. Cases have been reported in association with neurofibromatosis type 1, radiation therapy and thorotrast. There is nothing specific about gliosarcomas on imaging. They typically present as ring enhancing, intraaxial masses with shunting (early draining vein) and neovascularity on angiography.

The most likely diagnosis for this pattern is metastatic disease. Multiple astrocytomas are possible but would be less common. Multifocal astrocytoma refers to lesions which are attached to one another by at least a microscopic connection of tumor. Multicentric astrocytomas are not connected. Gliomatosis cerebri refers to an astrocytoma which diffusely infiltrates the white matter without enhancement or mass effect.

In the proper clinical setting, cerebral abscesses are a consideration, however they tend to present as lesions at the grey-white junction and would probably not show this degree of neovascularity and shunting. Lymphoma is not in the differential secondary to the pattern of ring enhancement and the lack of a deep grey or periventricular distribution typical of lymphoma. Immunocompromised patients may demonstrate central necrosis in primary CNS lymphoma. Acute demyelination could produce a pattern which mimics a ring enhancing mass (extemely unlikely here) and may be suggested by the patients clinical course or identification of other more typical MS lesions. Neither of these diagnoses would show these angiographic findings. Related Cases

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