Answer and Discussion of Quiz Set: N-007

2.    Which of the following tumors is a WHO grade I tumor?

A. Chordoid meningioma

B.  Papillary meningioma

C.  Clear cell meningioma

D.  Rhabdoid meningioma

E.  Secretory meningioma

Answer and Discussion: The answer is (E). Chordoid and clear cell meningioma are WHO grade II, papillar and rhabdoid meningioma is WHO grade III. The way to memorize this is to remember "CPR" for meningioma. Those that start with C, P, and R are WHO grade II or III tumor. Secetory meningioma when present without the presence of features indicating of behavior (such as brain invasion and over 4 mitoses per 10 high power fields) is a WHO grade I tumor. It should be noted that secretoy meningioma has a tendency to  cause a extensive edema disproportional to the tumor size. This featues, however, often prompt the radiologist and neurosurgeon to suspect malignancy.