Angioimmunoblastic T-cell lymphoma (AITL) can involve the bone marrow but can be challenging to diagnose.

T-cell angioimmunoblastic T-cell lymphomas arise from T follicular helper cells.



(1) positivity of immunohistochemical staining in an affected lymph node

(2) positivity of immunohistochemical stains in the bone marrow

(3) histologic pattern


Immunohistochemical stains to perform include:

(1) PD-1

(2) bcl-6


The tumor cells may stain with PD-1 and/or bcl-6.


The tumor in bone marrow may stain the same as the tumor in an involved lymph node but staining tends to be weaker.


Histologic patterns:

(1) interstitial/micronodular infiltrate with eosinophils

(2) interstitial/micronodular infiltrate without eosinophils

(3) diffuse infiltration with eosinophilia




no bone marrow involvement


diffuse involvement

median survival 80 months (fair)

IS/MN without eosinophils

up to 36 month survival

IS/MN with eosinophils

up to 18 month survival (poor)


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