craniopharyngioma
A benign, partly cystic, epithelial tumor of the sellar region, presumably derived from Rathke pouch epithelium. It affects mainly children and young adults. There are two clinicopathological forms: adamantinomatous craniopharyngioma and papillary craniopharyngioma. The most significant factor associated with recurrence is the extent of surgical resection, with lesions greater than 5 cm in diameter carrying a markedly worse prognosis. (Adapted from WHO)