title: Thyroid transcription factor 1 expression in sellar tumors: a histogenetic marker?
abstract: Pituicytomas are rare low-grade gliomas of the neurohypophysis. Their morphology and variable immunophenotype have led to speculation that they arise from pituicytes. Given the role of thyroid transcription factor 1 (TTF-1) in the developing rodent infundibulum and its expression in the adult rat neurohypophysis, we speculated that TTF-1 would be a marker of human pituicytes. Using immunohistochemistry, we found that TTF-1 is strongly expressed in fetal and adult human pituicytes. A survey of sellar masses demonstrated specific TTF-1 expression in pituicytomas (n = 3), atypical pituicytomas (n = 2), and granular cell tumors (n = 4), indicating a common pituicyte lineage. TTF-1 expression in spindle cell oncocytomas (n = 8) is less easily explained but invites speculation. Our observations may have implications for the classification of these rare sellar neoplasms, all the while acknowledging the morphological diversity of pituicyte-related neoplasms.
authors.affiliation: Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania 19106, USA. edward.lee@uphs.upenn.edu
authors.forename: Edward B
authors.initials: EB
authors.lastname: Lee
authors.forename: Tarik
authors.initials: T
authors.lastname: Tihan
authors.forename: Bernd W
authors.initials: BW
authors.lastname: Scheithauer
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Zhang
authors.forename: Nicholas K
authors.initials: NK
authors.lastname: Gonatas
mesh_terms: D000368:Aged; D005260:Female; D005333:Fetus; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005910:Glioma / Q000378:metabolism*; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000378:metabolism*; D010904:Pituitary Gland, Posterior / Q000378:metabolism / Q000473:pathology*; D010911:Pituitary Neoplasms / Q000378:metabolism*; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D005904:Glial Fibrillary Acidic Protein; D019394:Ki-67 Antigen; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors