| Neuroblastoma (Schwannianstroma-poor) |
| Definition: Neuroblastoma (Schwannianstroma-poor) composed of undifferentiated neuroblasts in the most part and interstitial components consist of Schwannian cells and fibroblasts are less than 50% of tumor tissue. |
| 1) Subtype |
| (1) Undifferentiated (The neuropil in the tumor are not clearly recognized.) |
| (2) Poorly differentiated (The tumor consists of less than 5% of ganglion like cells differentiation.) |
| (3) Differentiation (The tumor consists of more than 5% of ganglion like cells differentiation. |
| The definition of ganglion like cells differentiation: Size of cytoplasm is twice that of nucleus. The things of eosinophilic cytoplasm and eccentric nuclei in the cytoplasm. |
| 2) Mitosis karyorrhexis-index (MKI) |
| (1) low MKI , < 2% (less than 100 / 5000 cells) |
| (2) intermediate MKI, 2-4% (100-200/5000 cells) |
| (3) high MKI, >4% (more than 200/5000 cells) |
| The mitosis karyorrhexis index (MKI) is defined as the number of tumor cells with karyorrhexis and mitosis in the tumor tissues. MKI is classified with 3 categories according to the number of tumor cells in mitosis. |
