Small cell B-cell lymphoma, nodes of axilla and upper limb

This diagnosis code specifies a malignant neoplasm originating from small B-lymphocytes, specifically located within the lymph nodes of the axilla and/or upper limb. It represents a type of non-Hodgkin lymphoma characterized by small, abnormal B-cells.

This code is appropriate for patients diagnosed with small cell B-cell lymphoma confirmed to be present in the lymph nodes of the armpit or anywhere along the upper extremity. Documentation should clearly state the histological type of lymphoma as "small cell B-cell" and specify the involvement of axillary or upper limb lymph nodes, typically through biopsy results and imaging reports.

• Ensure the pathology report explicitly identifies "small cell B-cell lymphoma" and not another B-cell lymphoma subtype.
• Verify the anatomical site of involvement is limited to the axilla or upper limb lymph nodes; other sites require different codes.
• Do not confuse with other low-grade B-cell lymphomas that may have small cell morphology but are histologically distinct (e.g., follicular lymphoma, mantle cell lymphoma).