RESUMEN
We report a childhood case of thalamic atypical extraventricular neurocytoma that progressed to highly anaplastic ganglioglioma after 8 years of dormancy after subtotal resection and chemotherapy. The neurocytoma displayed immunoreactivity only for synaptophysin, ß-catenin, S100, and CD56. The ganglioglioma acquired strong immunoreactivity for chromogranin, glial fibrillary acidic protein, neuron-specific enolase, and p53 and showed a very high proliferation rate approaching 50% in some areas. Tumor transformation was associated with overexpression of components of the sonic hedgehog and Wnt developmental signaling pathways, which are known to regulate tumor-initiating cells in malignant brain neoplasms.
Asunto(s)
Neoplasias del Tronco Encefálico/patología , Transformación Celular Neoplásica/patología , Ganglioglioma/patología , Neurocitoma/patología , Tálamo/patología , Biomarcadores de Tumor/análisis , Biomarcadores de Tumor/genética , Biopsia , Neoplasias del Tronco Encefálico/química , Neoplasias del Tronco Encefálico/genética , Neoplasias del Tronco Encefálico/terapia , Proliferación Celular , Transformación Celular Neoplásica/química , Transformación Celular Neoplásica/genética , Niño , Progresión de la Enfermedad , Resultado Fatal , Femenino , Ganglioglioma/química , Ganglioglioma/genética , Humanos , Inmunohistoquímica , Lactante , Imagen por Resonancia Magnética , Neoplasia Residual , Neurocitoma/química , Neurocitoma/genética , Neurocitoma/terapia , Tálamo/química , Factores de TiempoRESUMEN
We report the presence of divergent populations of cells in a hypothalamic/chiasmatic pilomyxoid astrocytoma of an 11-month-old male, exhibiting differential immunohistochemical localizations for glial fibrillary acidic protein (GFAP) and synaptophysin. The tumor cells were negative for Neu-N and neurofilament protein. Ultrastructurally, the tumor comprised 2 cell types, one with features attributable to a neuronal phenotype alongside cells exhibiting an overt astroglial phenotype. This composite organization was confirmed by confocal microscopy, which revealed 2 distinct, albeit tightly interwoven, populations of GFAP and synaptophysin-labeled tumor cells. Our results indicate that a subset of the so-called pilomyxoid astrocytomas of the hypothalamic/chiasmatic region may represent phenotypically mixed glioneuronal neoplasms distinct from the pilocytic astrocytomas.