Meningiomas - radiation-induced

Case contributed by Frank Gaillard
Diagnosis certain

Presentation

HIstory withheld.

Patient Data

Age: 40 years
Gender: Female

Numerous masses are identified, all appearing extra-axial and demonstrating vivid contrast enhancement. The largest is on the left arising from the greater wing of sphenoid and exerting substantial mass effect. 

Numerous masses are identified, all appearing extra-axial and demonstrating vivid contrast enhancement. The largest is on the left arising from the greater wing of sphenoid and exerting substantial mass effect. Prominent central spoke-wheel vascularity is noted. Features are those of meningiomas. No other tumors (e.g. schwannomas) identified. 

Case Discussion

The patient went on to have surgery with resection of the largest left-sided mass. This confirmed the diagnosis of meningioma

Histology

The paraffin sections show a variably hypercellular dural based tumor. Tumor cells are a mixture of epithelioid and spindle morphology and are arranged in diffuse sheets and loose fasciculi. In many areas, a chordoid appearance is also noted with solid aggregates and cords of epithelioid tumor cells dispersed within a myxomatous stroma. Tumor cells show moderate nuclear pleomorphism and an occasional mitotic figure is identified (1/20 HPF). No areas of necrosis are seen. There is no brain invasion.

Immunohistochemistry shows strong nuclear staining in tumor cells for progesterone receptor (PgR) and strong membrane staining for epithelial membrane antigen (EMA). There is also moderate staining for bcl-2 and patchy moderate staining for smooth muscle actin (SMA). No staining for CD34, ALK-1, desmin or pancytokeratin AE1/AE3 is seen in tumor cells.

FINAL DIAGNOSIS: chordoid meningioma (WHO grade II).

Discussion

This patient had a remote history of cranial irradiation as part of treatment for childhood leukemia. These tumors are therefore likely to represent radiation-induced meningiomas. The other possibility is that the smaller tumors could represent CSF dissemination of the chordoid meningioma 1, although these appear all pachymeningeal rather than leptomeningeal. 

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