Source:http://linkedlifedata.com/resource/umls/id/C2986561
NCI: A very rare, WHO grade I, non-endocrine neoplasm that arises in the anterior lobe of the pituitary gland and described in adults. Its histogenesis is uncertain, although it has been suggested that it is derived from the folliculo-stellate cells of the adenohypophysis. It is characterized by the presence of spindle cells with eosinophilic, granular cytoplasm forming fascicles. Electron microscopic studies demonstrate the accumulation of intracytoplasmic mitochondria and lack of secretory granules. Immunohistochemical studies are negative for pituitary hormones. Patients may present with pituitary hypofunction, visual disturbances, headache, nausea and vomiting. The clinical course is usually benign.