Code the degree of differentiation or grade stated in the
FINAL pathologic diagnosis only.
Microscopic Description: Moderately differentiated squamous cell
carcinoma with poorly differentiated areas
Final Pathologic Diagnosis: Moderately differentiated squamous
Code to the final diagnosis: Moderately differentiated '2'.
Usually there will be no statement as to grade for in situ lesions.
However, if a grade is stated, it should be coded.
When there is variation in the usual terms for degree of differentiation,
code to the higher grade as specified below:
TERM GRADE CODE
Low grade I-II 2
Medium grade II-III 3
High grade III-IV 4
Partially well differentiated I-II 2
Moderately undifferentiated III 3
Relatively undifferentiated III 3
Grade coding for prostate cases using Gleason's score or pattern.
1. If Gleason's score (2-10) is given code as follows:
Gleason's score Grading
2, 3, 4 I Well Differentiated
5, 6, 7 II Moderately Differentiated
8, 9, 10 III Poorly Differentiated
2. If Gleason's pattern (1-5) is given code as follows:
If a diagnosis indicates two different degrees of grade or
Gleason's pattern Grading
1-2 I Well Differentiated
3 II Moderately Differentiated
4-5 III Poorly Differentiated
For lymphomas and leukemias designation of T-cell, B-cell, and null cell:
Code the results of marker studies. Code the final pathologic diagnosis
of T-cell, B-cell or null cell if marker studies are not documented
differentiation (e.g. "well and poorly differentiated"; or "grade
in the patient record. (See page 2 of ICD-O, FT, 1987.)
For lymphomas and leukemias, information on T-cell, B-cell or null cell
has precedence over information on grading or differentiation.
II-III"; or "well differentiated grade II"), code to the higher grade
code (Rule 10, page xxxi in ICD-O, 1990).