Answer and Discussion of Quiz Set: N-027

4.    Which of the followings is not true about chordoid meningioma and chordoma?

A.  Both of them typically have a bluish, myxomatous to chondroid background that is strongly positive for Alcian blue.

B.  Both of them can be positive for cytokeratin and epithelial membrane antigen (EMA).

C.  Both of them can be positive for S100 protein and immunoreactivity is typically patchy.

D.  Both of them are typically dural based.

E.  Chordoma but not chordoid meningioma is positive for Brachyury.

Answer and Discussion: The answer is (D). The location is a very important hint in the differential diagnosis. Meningiomas are typically dural based and can occur essentially any where in the brain with predilection to areas with leptomeninges. Intracranial chordomas, in contrast, arise from the clivus. They may also occur in the sacrum, and much less frequently, along the spine. Chordormas arise from the bone and is not dural based.