Case 3

Gregory Pinsky, MD, PhDSouthern California Permanente

Medical Group

Case History

• 44 years old female presented in ER with severe headache. CT was ordered.

CT-scan (no contrast)

CT-scan (no contrast)

• Frontal lobe mass with associated edema

Surgery

• Tumor resection was performed

H&E SECTIONS

Histological findings

• Histologically, tumor is characterized by cells with elongated processes and by a loose myxoid background, giving the appearance of many microcysts.

• Pleomorphic cells focally evident• The tumor show foci of typical

meningothelial whorls.

Differential Diagnosis

• Meningioma (if any – what type?)• Glial neoplasm• ????

Immunohistochemistry

• EMA• GFAP• Cytokeratin

Cytokeratin

GFAP

GBM

GFAP

GBM

GFAP

• NEGATIVE IN TUMOR CELLS

EMA

Diagnosis: Microcystic Meningioma (WHO grade 1)

Microcystic meningioma

• Distinctive subtype of meningioma• Must be differentiated from chordoid

meningioma (WHO grade II)• Microcystic gliomas• Hemangioblastomas• Myxoid schwannomas

Microcystic meningioma• Microcystic meningiomas have occasionally

been designated as "humid" meningiomas because of the soft, moist appearing cut surface. Microscopically they contain myriads of intracellular and intercellular spaces that are filled with fluid having a low protein content. Their behavior is similar to other benign meningiomas; however, the unusual histological appearance can lead to confusion with glial neoplasms. The meningeal nature of these tumors can be confirmed with immunostaining for epithelial membrane antigen. Vessels in these neoplasms may be markedly thickened.