V_3_5 Grade and Differentiation

V.3.5 Grade and Differentiation

Grade, or degree of differentiation, describes the tumor’s resemblance to normal tissue. Well differentiated (Grade 1) is the most like normal tissue, and undifferentiated (Grade 4) is the least like normal tissue. Grades 5-8 define particular cell lines for lymphomas and leukemias.

Priority order for coding grade:

Site specific grade systems, See Sections V.3.5.6 – 9 (available below)
Differentiation See Section V.3.5.3
Nuclear Grade
Terminology (See table below)

Instructions:

Code grade stated in the final pathologic diagnosis.
If there is a difference in grade between two pathologic specimens, code to the highest known grade over an unknown grade (Exception: Non-Invasive Bladder - see below).
Grade stated in a pathology report takes precedence over one stated in a cytology report.
Relevant information in the microscopic description can be used in the absence of a pathologic statement.
AJCC staging form may be used if it is signed by a physician and the only available information.

Code Grade 9 (unknown):

Primary site is unknown.
Needle biopsy or excisional biopsy of a primary site has a differentiation given and the excision or resection does not, code the information from the needle/incisional biopsy.
No grade provided for the primary site, even if a grade is given for a metastatic site.
Pathology is after neoadjuvant therapy or it is unknown whether the pathology is before or after neoadjuvant therapy.
High grade dysplasia (adenocarcinoma in situ).
FIGO grade is only grade provided.
ONLY Non-Invasive Bladder tumor histology codes 8120/2, transitional cell (urothelial) carcinoma in situ, and 8130/2, papillary transitional cell (papillary urothelial) noninvasive carcinoma (See DSQC Memo #2010-01).

The terminology codes are:

Code	Description
1	Grade I grade i grade 1 Well differentiated Differentiated, NOS
2	Grade II grade ii grade 2 Moderately differentiated Moderately well differentiated Partially well differentiated Partially differentiated Intermediate differentiation Low grade, NOS
3	Grade III grade iii grade 3 Poorly differentiated Moderately undifferentiated Relatively undifferentiated Slightly differentiated Dedifferentiated Medium grade, NOS
4	Grade IV grade iv grade 4 Undifferentiated Anaplastic High grade, NOS
5**	T-Cell T-Precursor
6**	B-Cell Pre B B-Precursor
7**	Null Cell Non-T–Non-B
8**	NK (Natural Killer Cell)
9	Grade or Differentiation Not Determined or Not Stated

**Apply to leukemias and lymphomas only. See Section V.3.5.7.

See Section II.1.9.7 WHO Grade

See Section V.3.5.6 Gleason's Score

See Section V.3.5.7 Lymphomas and Leukemias

See Section V3.5.8 Bloom-Richardson Grade for Breast Cancer

See Section V.3.5.9 Grading Astrocytomas

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