12/1/2009 Case 2: Clear cell variant of meningioma WHO grade II

Presented by: Dr. Adrian Chan and Dr. Irina Mikolaenko - NYU Medical Center

Clinical History:

The patient is a 65-year-old woman with a history of hypertension, diabetes mellitus, hyperlipidemia, right breast cancer, S/P mastectomy plus XRT in 1990, who developed a feeling of "pressure behind the forehead" for a month. She was found on brain MRI to have a large right frontoparietal mass. The patient mainly takes medication for hypertension. There is no family history of malignancy. MRI Brain:  3.7 x 2.7 x 3.7 cm avidly enhancing, T1 hypodense and T2 hyperintense right frontal extra-axial mass with significant surrounding vasogenic edema, with mass effect and midline shift. There is hyperostosis of the adjacent right frontal bone with an enhancing nodule.

The neuropathology of this case is not the slide that was sent as NYU 2009-2.  The neurohistology showed a moderately cellular collagen-producinG tumor with clear-cell, spindle cell and compact areas.  Nuclei were ovoid.  PAS was strongly positive and the reaction product was removed with diastase.  Immunohistochemistry showed that EMA was strongly positive and PR was rarely positive.  There was moderate MIB1 staining.

Diagnostic Notes:

The diagnosis was Clear cell meningioma, WHO Grade II.  The definition of WHO II meningiomas includes certain histological variants with an increased chance of recurrence, including the clear cell pattern.  Clear cell meningiomas make up 0.2% of all meningiomas and recurrence happens in 22-61% of cases.  There is a tendency for children and young adults to be affected and F:M ratio is 1.25:1.  Sites where this variant occurs, which are unusual for meningiomas in general, include the cerebellopontine angle, and cauda equina.  Progesterone receptors are found in 77% of cases, and there is occasional CSF seeding.

The chordoid pattern is another variant of meningioma that indicates a WHO Grade of II.

Slide Image:

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