Key points for the differential diagnosis of cell-dense and matrix-rich types according to the ultrastructures of chordomasa
| Cell-Dense Type | Matrix-Rich Type | |
|---|---|---|
| Tumor cell content in a low-power field (×3000) | Densely arranged | Seldom or none |
| Extracellular matrix content | Relatively sparse | Abundant |
| Complex of rough endoplasmic reticulum and the mitochondria | Rich | Relatively seldom |
| Nuclei and chromatin | Abnormal nuclei with condensed, deeply staining heterochromatin | Regularly shaped nuclei, mainly with loosely arranged euchromatin |
| Cell junctions | Desmosomes are obvious | Few desmosomes |
| Collagen fibrils | Type III collagen fibrils can be found | Seldom |
| Exocytosis | Easily found | Seldom |
↵a Reprinted with permission from Bai et al13 and Elsevier.