Morphology & Grade
Major Cellular Classifications for Non-Hodgkin Lymphomas (now considered obsolete)Nodular/follicular Histiocytic Diffuse Lymphocytic poorly differentiated/well differentiated
6th Digit Morphology (Grade/Differentiation)
The sixth digit (behavior/differentiation) of the morphology code can be added to the cell types of lymphomas that have been identified by surface marker studies. Code any statement of T-cell or B-cell involvement whether or not marker studies are documented in the patient record.
- Well differentiated
- Moderately differentiated
- Poorly differentiated
- Null cell (no longer for leukemias only)
- NK cell (new for 1995 cases and after)
- Not determined, not graded
For lymphomas, information on T-cell and B-cell has precedence over information on grading or differentiation.
For lymphomas, do not code the descriptions "high grade," "low grade," or "intermediate grade" in the 6th digit grade or differentiation field. These terms refer to categories in the Working Formulation and not to histologic grade.
Most lymphoblastic lymphomas are T-cell. With the exception of the immunoblastic large cell lymphomas and the mixed small and large cell diffuse lymphoma, most of the rest are B-cell.
The following lymphoma morphologies and codes were added to ICD-O-2 starting with Jan. 1, 1995 diagnoses:
|Synonym (S) or
New Term (T)
|S||9673/3||Mantle cell lymphoma|
|T||9688/3||T-cell rich B-cell lymphoma|
|T||9708/3||Subcutaneous panniculitic T-cell lymphoma|
|T||9710/3||Marginal zone lymphoma, NOS|
|S||9714/3||Anaplastic large cell lymphoma (ALCL), CD30+|
|T||9715/3||Nucosal-Associated Lymphoid Tissue (MALT) lymphoma|
|T||9716/3||Hepatosplenic γδ(gamma - delta) cell lymphoma|
|T||9717/3||Intestinal T-cell lymphoma|
|TS||9717/3||Enteropathy associated T-cell lymphoma|