Mediastnl lg B-cell lymph, nodes of ing rgn and lower limb

This code describes a specific type of aggressive non-Hodgkin lymphoma, mediastinal large B-cell lymphoma, when it has metastasized to or originated in the lymph nodes of the inguinal region and/or lower limb. This is a rare subtype typically presenting as a large mediastinal mass, but this code specifies involvement in distant lymph node sites.

Use this code when documentation clearly indicates a diagnosis of mediastinal (thymic) large B-cell lymphoma with confirmed involvement of lymph nodes in the groin or leg. This diagnosis requires pathological confirmation of the specific lymphoma subtype and imaging or biopsy evidence of involvement in the specified anatomical sites.

• Ensure the pathology report specifically identifies "mediastinal (thymic) large B-cell lymphoma" and not another large B-cell lymphoma subtype.
• Verify that the documentation explicitly states involvement of inguinal region and/or lower limb lymph nodes.
• Do not use for primary mediastinal involvement without documented spread to the specified peripheral lymph nodes.