title: Prolactin-secreting pituitary tumor in early adolescence: hormonal and electron microscopical studies.
abstract: A 13-year-old boy was evaluated for an enlarged sella. There were no consistent visual field defects, and carotid arteriograms and pneumoencephalograms showed no extrasellar abnormality. The endocrine workup demonstrated a subnormal growth hormone reserve. The only other, but most striking abnormality, was an excessively high serum prolactin level, which was partially suppressed with levodopa. A chromophobe pituitary tumor was removed that had histological features suggestive of malignant neoplasm. Characteristics of a prolactin-secreting tumor were confirmed by electron microscopy. The serum prolactin levels decreased substantially  after surgery and further after a course of pituitary irradiation; however, they continue to be elevated above normal. Prolactin determinations play in integral part in the evaluation for a possible pituitary tumor-not only for diagnostic purposes, but also to provide a parameter of future tumor activity in an established case. Electron microscopical studies are helpful in identifying the tumor as source of the excessive prolactin secretion.
mesh_terms: D000238:Adenoma, Chromophobe / Q000097:blood / Q000378:metabolism* / Q000648:ultrastructure; D000293:Adolescent; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D005089:Exocytosis; D005951:Glucose Tolerance Test; D013006:Growth Hormone / Q000097:blood; D006801:Humans; D008297:Male; D010902:Pituitary Gland / Q000648:ultrastructure; D010911:Pituitary Neoplasms / Q000097:blood / Q000378:metabolism* / Q000648:ultrastructure; D011388:Prolactin / Q000097:blood / Q000378:metabolism*
chemical_list: D011388:Prolactin; D013006:Growth Hormone