Late development of intraventricular papillary pituitary carcinoma after irradiation of prolactinoma. 
Intracranial dissemination of pituitary adenomas is a rare event that does not equate malignancy.  Most of the cases have been reported as metastases from pituitary carcinoma.  A case of papillary pituitary carcinoma developed 12 years after radiotherapy for prolactin-secreting hormone pituitary adenoma is presented.  A 37-year-old woman was admitted for the second time with neurologic disturbance and hypertension.  A gadolinium-enhanced magnetic resonance scan of the brain demonstrated a 50-mm enhanced mass (absent on previous studies) on the lateral ventricle, involving the left temporal lobe.  The patient underwent a craniotomy and biopsy of the lesion that was consistent with pituitary carcinoma; it was immunoreactive to follicle-stimulating hormone, adrenocorticotropic hormone, pituitary tumor-transforming gene, and epithelial cell adhesion molecule.  Transmission electron microscopy analysis confirmed the secretory pituitary tumor diagnosis.  The tumor was considered a primary pituitary papillary carcinoma.  The clinical course indicated that this tumor was the seedling of a pituitary tumor, although it could be interpreted as metastases from a pituitary carcinoma.