Tumors of the Neurohypophysis

Gliomas in this region are commonly astrocytomas, mostly of the pilocytic type.

Granular-cell tumor is generally benign, noninva-sive, situated in the sella or supra- or parasellar region, figure 1 1.32

Pituitary chromophobe (null-cell) adenoma. A. The cells are separated into groups by sinusoidal tabeculae. B. They display a small nucleus, variable amount of cytoplasm, and slight pleomorphism.

figure 1 1.32

Pituitary chromophobe (null-cell) adenoma. A. The cells are separated into groups by sinusoidal tabeculae. B. They display a small nucleus, variable amount of cytoplasm, and slight pleomorphism.

table 1 1.8.

Nonpituitary Tumors

in the Sellar Region

Meningioma

Epidermoid, dermoid cysts

Craniopharyngioma

Teratoma

Germinoma

Lipoma

Glioma

Chordoma

Hamartoma

Metastasis

or in the third ventricle. Its cellular origin is controversial, as reflected by the various names given to it: choristoma, referring to the nests of large, granulated, dusty cells in the infundibular region; granular cell myoblas-toma, implying a mesenchymal origin; and pituicytoma, suggesting an origin from the neurohypophysis. The tumor occurs most frequently in middle-aged women and presents with visual impairment, enlarged sella, and endocrine disturbances.

Grossly, the tumor is circumscribed, firm, and lobu-lated. Histologically, it consists of large, polygonal-shaped cells, loosely arranged in sheets. Their perikaryons contain eosinophilic and PAS-positive granules and an eccentric nucleus. Hormonal immunohistochemistry studies are negative.

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