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| Code | Description |
|---|---|
| 1 | G1: Spindle cell melanoma (>90% spindle cells) |
| 2 | G2: Mixed cell melanoma (>10% epithelioid cells and <90% spindle cells) |
| 3 | G3: Epithelioid cell melanoma (>90% epithelioid cells) |
| A | Well differentiated |
| B | Moderately differentiated |
| C | Poorly differentiated |
| D | Undifferentiated, anaplastic |
| 9 | Grade cannot be assessed (GX); Unknown |
