A slowly growing benign brain mass

(A–H) T2-weighted images (repetition time msec/echo time msec, 2,150/30; 3-mm-thick sections; matrix, 256 × 256; field of view 250 mm²) show a neuroglial cyst in the right hemisphere measuring 16 cm³ initially and increasing to 175 cm³ with considerable mass effect after 7 years.