A 10-year-old child with new onset of visual field abnormalities and diabetes insipidus undergoes a head CT. The CT scan demonstrates a 3cm mass lesion with focal calcification involving the area above the sella turcica. Needle biopsy of this mass shows that the tumor is composed of tissue resembling tooth enamel. Which of the following diagnoses is most likely?
The tumor is a craniopharyngioma, alternatively known as an adamantinoma or ameloblastoma. Craniopharyngiomas may arise in, or more commonly above, the sella turcica. The histological pattern recapitulates the enamel organ of the tooth, with nests or cords of stratified squamous or columnar epithelium embedded in a loose fibrous stroma. Calcification (and even metaplastic bone formation) is common in these benign tumors, which are thought to arise from vestigial remnants of Rathke's pouch. Glioblastoma multiforme characteristically shows at least some enlarged cells with bizarre nuclei. Large pituitary adenomas contain nests of uniform glandular cells. Medulloblastoma is made of small basophilic cells with relatively large nuclei for their size.
Craniopharyngioma
Glioblastoma multiforme
Large pituitary adenoma
Medulloblastoma