Data Last Updated: Dec. 17, 2025

Schema Discriminator 1: Histology Discriminator for 9591/3

This input is used for staging

Description

There are multiple hematopoietic terms that have the same ICD-O histology code (9591/3). However, for purposes of stage grouping AJCC 8th edition, they are in different chapters. A schema discriminator is necessary to distinguish between these histology terms so that the appropriate sub(chapter)/schema is used.

Rationale

A schema discriminator is used to assign AJCC ID when site and histology alone are insufficient to identify the applicable AJCC staging method and to assign Schema ID, which links each case to the appropriate SSDIs, Grade, Summary Stage and EOD data collection system.

Additional Info

**Source documents:** pathology report

Notes

**Note:** **Schema Discriminator for 9591/3** * A schema discriminator is used to discriminate for histology 9591/3: Non-Hodgkin lymphoma to determine which Stage Group table to use.

Coding Guidelines

**1)** **Code 1**: Splenic B-cell lymphoma/leukemia, unclassifiable * **a.** Abstracted and staged as a **leukemia** **2)** **Code 2**: Hairy cell leukemia variant * **a.** Abstracted and staged as a **leukemia** **3)** **Code 3**: Splenic diffuse red pulp small B-cell lymphoma * **a.** Abstracted and staged as a **lymphoma** **4)** **Code 4**: Non-Hodgkin lymphoma, NOS * **a.** Abstracted and staged as a **lymphoma**
Code Description Schema ID #/Description
1 Splenic B-cell lymphoma/leukemia, unclassifiable 00830: HemeRetic
2 Hairy cell leukemia variant
Prolymphocytic variant of hairy cell leukemia		 00830: HemeRetic
3 Splenic diffuse red pulp small B-cell lymphoma
Splenic marginal zone lymphoma, diffuse variant
Splenic red pulp lymphoma with numerous basophilic villous lymphocytes
Splenic lymphoma with villous lymphocytes		 00790: Lymphoma (excluding CLL/SLL)
9 Non-Hodgkin lymphoma, NOS
Any other terminology describing non-Hodgkin lymphoma, NOS		 00790: Lymphoma (excluding CLL/SLL)
<BLANK> Histology is NOT 9591, Discriminator is not necessary