title: The clinicopathological features of pituicytoma and the differential diagnosis of sellar glioma.
abstract: Pituicytoma is rare and difficult to diagnose. This study explored the clinicopathological features, immunophenotype and differential diagnosis of pituicytoma. We compared 11 cases of pituicytoma and 26 cases of sellar glioma (16 pilocytic astrocytomas, four diffuse astrocytomas, three pilomyxoid astrocytomas, and three third ventricle chordoid gliomas). The 11 pituicytoma cases involved six men and five women (age: 33-65 years). Three of the 11 patients experienced recurrence due to a residual tumor, and one patient underwent three surgeries during a 6-month period. Imaging findings revealed tumors were in the intrasellar region (four cases), suprasellar region (four cases) and intra-suprasellar regions (three cases). The tumor diameters were 1.3-3.8 cm, and the preoperative diagnoses were pituitary adenoma, craniopharyngioma and meningioma. The tumors were solid and contained spindle or slightly chubby cells that were densely arranged with visible cleft-like or expanded sinusoid structures. The cells had vague boundaries, circular nuclei, fine chromatin, and a small nucleolus. Immunohistochemical staining of the pituicytomas revealed positive expression of thyroid transcription factor-1 (TTF-1) and S-100 protein (S-100), positive focal expression of glial GFAP;(five of 11 cases), and negative oligodendrocyte transcription factor 2 (Olig2), CD34 and neurofilament expression. The Ki67 index was 6% in one case and 1-2% in the other cases. Unlike pituicytoma, most sellar glioma cases exhibited GFAP and Olig2 expression, and negative TTF-1 expression. Third ventricle chordoid gliomas expressed TTF-1, GFAP and CD34, and were negative for Olig2. Our results indicate that pituicytoma typically involves dense arrangements of spindle or slightly chubby cells. The morphology is occasionally atypical, with ependymoma-like or meningioma-like structures, and occasionally exhibits pilomyxoid degeneration. Abundant sinusoids are characteristic of hemorrhagic tumors. The dense spindle cell arrangement is a relatively specific morphology, and staining for GFAP, TTF-1, Olig2 and CD4 may help differentiate pituicytoma from sellar glioma.
authors.affiliation: Department of Neuropathology, Beijing Neurosurgical Institute, Capital Medical University, China National Clinical Research Center for Neurological Diseases, NCRC-ND, Center of Brain Tumor, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Brian Tumor, Beijing, China.
authors.forename: Junmei
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Neuropathology, Beijing Neurosurgical Institute, Capital Medical University, China National Clinical Research Center for Neurological Diseases, NCRC-ND, Center of Brain Tumor, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Brian Tumor, Beijing, China.
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Neuropathology, Beijing Neurosurgical Institute, Capital Medical University, China National Clinical Research Center for Neurological Diseases, NCRC-ND, Center of Brain Tumor, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Brian Tumor, Beijing, China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Du
authors.affiliation: Department of Neuropathology, Beijing Neurosurgical Institute, Capital Medical University, China National Clinical Research Center for Neurological Diseases, NCRC-ND, Center of Brain Tumor, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Brian Tumor, Beijing, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Cui
authors.affiliation: Department of Neuropathology, Beijing Neurosurgical Institute, Capital Medical University, China National Clinical Research Center for Neurological Diseases, NCRC-ND, Center of Brain Tumor, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Brian Tumor, Beijing, China.
authors.forename: Jingyi
authors.initials: J
authors.lastname: Fang
authors.affiliation: Department of Neuropathology, Beijing Neurosurgical Institute, Capital Medical University, China National Clinical Research Center for Neurological Diseases, NCRC-ND, Center of Brain Tumor, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Brian Tumor, Beijing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Neuropathology, Beijing Neurosurgical Institute, Capital Medical University, China National Clinical Research Center for Neurological Diseases, NCRC-ND, Center of Brain Tumor, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Brian Tumor, Beijing, China.
authors.forename: Guilin
authors.initials: G
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D003397:Craniopharyngioma / Q000000981:diagnostic imaging / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology*; D012658:Sella Turcica / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor
keywords: TTF-1; immunohistochemistry; pituicytoma; sellar glioma; third ventricle chordoid glioma