Grading MRI of a<unk>  in an 18-year-old boy. Sagittal T1+Gd.<unk>  (PTPR) is a recently described neoplasm that has been formally recognized in the 2007 World Health Organization (WHO) “Classification of<unk>  of the Nervous System.” Because these<unk>  are so rare, at first there was really no way to grade these<unk> . Once they were biopsied, they were defined as either malignant, meaning cancerous, or benign, meaning cancer free. After seeing more and more cases of this<unk>  they are now determined to be either Grade II or Grade III, according to the WHO classification. The mitotic activity varies for these<unk> , ranging from 0 to 10 mitoses per 10 high power (x40) fields. Grade II Grade II<unk>  are relatively slow growing. They have a slightly abnormal microscopic appearance and can spread into nearby normal tissue. Grade II<unk>  can also recur as a higher-grade<unk>  Grade III Grade III<unk>  are malignant. In these types of<unk>  the cells are actively reproducing abnormal cells. The cells of the<unk> will often grow into nearby normal brain tissue. Grade III<unk>  tend to recur as higher-grade<unk> .
Papillary tumors of the pineal region
Optic nerve sheath meningioma
Intraocular schwannoma
Optic nerve glioma
Pituitary adenoma
Extracranial germ cell tumor
Optic nerve tumor
Central nervous system cavernous hemangioma