Molecular Biology and Genetics of Chordomas

Abstract

Chordomas are extra-axial, low-grade malignancies growing slowly, located anywhere from the clivus to the sacrum on the axial skeleton. Grossly they are unencapsulated, usually lobulated, pink-gray colored, invasive tumors with foci of hemorrhage and calcifications exhibiting epithelial phenotype. Histopathologically they are classified as classic chordomas, chondroid chordomas, and atypical chordomas. Classic chordomas are characterized by the presence of physaliferous cells which are large, vacuolated, mucus-containing cells with hyperchromatic, eccentric nuclei having prominent nucleoli rarely demonstrating atypia and reticulated cytoplasm due to intracellular accumulation of glycosaminoglycans, similar to the cells of notochord. The cytoplasm is eosinophilic and stains positive with the periodic acid Schiff stain. Other cell types are stellate cells and intermediate or transitional cells.