title: Mixed Gangliocytoma-Pituitary Adenoma: Insights on the Pathogenesis of a Rare Sellar Tumor.
abstract: Gangliocytomas originating in the sellar region are rare; most are tumors composed of gangliocytic and pituitary adenomatous elements, forming the so-called mixed gangliocytoma-pituitary adenoma. The majority of mixed gangliocytoma adenomas are associated with endocrinopathies, mainly acromegaly and less often Cushing disease and hyperprolactinemia. In the present study, 10 cases of mixed gangliocytoma and somatotroph adenomas were evaluated for patterns of cellular differentiation and expression of lineage-specific transcription factors. The tumors were characterized by immunohistochemistry for pituitary hormones, cytokeratins, Pit-1, and the neuronal markers NeuN, neurofilaments (NFP), and MAP2. Double-labeling immunohistochemistry for Pit-1/GH, Pit-1/NFP, Pit-1/MAP2, and NeuN/GH was performed in 9/10 tumors. Our data demonstrate that both adenomatous and ganglionic cells express the acidophilic lineage transcription factor Pit-1. Although mixed gangliocytomas and somatotroph adenomas show histologically distinct cellular populations, there is at least a small population of cells that coexpress the Pit-1 transcription factor and neuronal-associated cytoskeletal proteins favoring the theory of transdifferentiation of neuroendocrine cells into neuronal elements of these mixed tumors.
authors.affiliation: Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA.
authors.forename: M Beatriz S
authors.initials: MB
authors.lastname: Lopes
authors.forename: Emily
authors.initials: E
authors.lastname: Sloan
authors.forename: Julie
authors.initials: J
authors.lastname: Polder
mesh_terms: D000236:Adenoma / Q000737:chemistry / Q000473:pathology*; D000328:Adult; D034961:Antigens, Nuclear / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis; D001706:Biopsy; D002454:Cell Differentiation; D019070:Cell Lineage; D005260:Female; D005729:Ganglioneuroma / Q000737:chemistry / Q000473:pathology*; D006728:Hormones / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis; D008297:Male; D008869:Microtubule-Associated Proteins / Q000032:analysis; D008875:Middle Aged; D018193:Neoplasms, Complex and Mixed; D009419:Nerve Tissue Proteins / Q000032:analysis; D016900:Neurofilament Proteins / Q000032:analysis; D010911:Pituitary Neoplasms / Q000737:chemistry / Q000473:pathology*; D050817:Transcription Factor Pit-1 / Q000032:analysis
chemical_list: D034961:Antigens, Nuclear; D014408:Biomarkers, Tumor; D006728:Hormones; C489788:MAP2 protein, human; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D016900:Neurofilament Proteins; C494187:POU1F1 protein, human; D050817:Transcription Factor Pit-1; C506808:neuronal nuclear antigen NeuN, human; D007633:Keratins