title: A case of atypical granular cell tumor of the neurohypophysis.
abstract: A case of granular cell tumor (GCT) arising in the neurohypophysis of a 63-year-old woman is reported. The tumor consisted of ovoid, polygonal or spindle-shaped cells in a sheet-like or fascicular arrangement. Its abundant cytoplasm contained granules positive for diastase-resistant periodic acid-Schiff reaction. Ultrastructurally, the tumor cells contained numerous polymorphic lysosomes of various densities. Immunohistochemically, the tumor cells were positive for S-100 protein, glial fibrillary acidic protein and Leu7, suggesting that the tumor originated from pituicytes that were thought to be modified astrocytes in the neurohypophysis and its stalk. The granular cells showed nuclear atypia, pleomorphism and increased mitotic activity. Therefore, the present tumor was considered as a histologically atypical GCT. Interestingly, proliferating cell nuclear antigen, Ki-67 and p53 were stained in a few tumor cells of this case. These findings indicate that the present tumor had a malignant potential.
authors.affiliation: First Department of Pathology, Faculty of Medicine, Kanazawa University, Kanazawa, Japan. s.kasa@med.kanazawa-u.ac.jp
authors.forename: S
authors.initials: S
authors.lastname: Kasashima
authors.forename: Y
authors.initials: Y
authors.lastname: Oda
authors.forename: J
authors.initials: J
authors.lastname: Nozaki
authors.forename: M
authors.initials: M
authors.lastname: Shirasaki
authors.forename: I
authors.initials: I
authors.lastname: Nakanishi
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D005260:Female; D016586:Granular Cell Tumor / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007124:Immunoenzyme Techniques; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis; D010904:Pituitary Gland, Posterior / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D010911:Pituitary Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins