Site-Specific Factor 9
Mitotic Count
Notes
**Note 1:** The mitotic count, the number of mitoses per 40 high-power fields (HPF), reflects the potential aggressiveness or prognosis of uveal melanomas. This site-specific factor presumes the denominator of 40 HPF, so just the numerator (the mitotic count) is coded here. * For other schemas in which mitotic count is collected, the denominator may vary **Note 2:** An HPF usually has a magnification objective of 40 (a 40x field). As described in the AJCC chapter on uveal melanomas, the typical field area is 0.15 - 0.19 square millimeters (mm). (1) **Note 3:** Record mitotic count to the nearest tenth as documented in the pathology report. * For example, a mitotic count of 6/40 HPF would be coded 060 **Note 4:** Code the specific mitotic count only per 40 HPF; assume the denominator is 40 HPF if not specified. * Use code 996 only if the mitotic count is expressed with a specific denominator other than 40 HPFDefault
988NAACCR Item
NAACCR #2863Metadata
None| Code | Description |
|---|---|
| 000 | 0 mitoses per 40 high-power fields (HPF) (40x field) Mitoses absent, no mitoses present, no mitotic activity |
| 001-008 | 0.1 - 0.8 mitosis per 40 HPF (40x field) |
| 009 | 0.9 mitosis per 40 HPF (40x field) Stated as less than 1 mitosis per 40 HPF (40x field) |
| 010-100 | 1 - 10 mitoses per 40 HPF (40x field) |
| 110 | 11 or more mitoses per 40 HPF (40x field) |
| 988 | Not applicable: Information not collected for this case |
| 990 | Stated as low mitotic count or rate with no specific number |
| 991 | Stated as high mitotic count or rate with no specific number |
| 996 | Mitotic count described with denominator other than 40 HPF (40x field) |
| 998 | No histologic specimen from primary site |
| 999 | Unknown or no information Not documented in patient record |