| Popis: |
Primitive neuroectodermal or neuroepithelial tumors are names used to describe neoplasias composed of undifferentiated cells resembling germinal cells of the embryonic neural tube. These tumors are small round cell malignancies of the neural crest origin arising outside the central and sympathetic nervous system. They are described as peripheral and central neuroectodermal tumors related to the original malignant cell. A great number of tumors are described under this classification in spite of the fact that there is no an universal acceptance that these small-cell neoplasms, regardless of their primary site, are derived from immature neuroectoderm tissue. Because one tumor resembles others in terms of its phenotypic expression, multiple specific studies such as clinical profile, ultrastructural, immunocytochemical, and cytogenetic features should be studied, since no single clinical or laboratory marker is by itself diagnostic. However, there is a chromosomal reciprocal translocation, t(11;22)(q24;q12), which is unique to Primitive Neuroectodermal Tumor (PNET). |
