Angioimmunoblastic T Cell Lymphoma
Definition
- T cell lymphoma of probable germinal center T cell origin, characterized by a polymorphous infiltrate with a prominent proliferation of high endothelial venules and follicular dendritic cells, frequently with marked constitutional symptoms
Alternate/Historical Names
- Angioimmunoblastic lymphadenopathy with dysproteinemia (AILD)-type T cell lymphoma
- Angioimmunoblastic-type T cell lymphoma
- Immunoblastic lymphadenopathy
- Lymphogranulomatosis X
Historical note
- Angioimmunoblastic lymphadenopathy was originally felt to be a precursor lesion that in some cases evolved into T cell lymphoma
- Presence in most cases of clonal T cell receptor gene rearrangements has led to re-classification as T cell lymphoma, even when the malignant T cell population is not histologically evident
Diagnostic Criteria
- Loss of normal lymph node architecture
- Atretic or absent germinal centers
- Prominent arborizing high endothelial venules with PAS positive amorphous perivascular material
- Patent subcapsular sinus, even in the presence of extracapsular extension
- Diffuse polymorphous paracortical infiltrate including lymphocytes, immunoblasts,plasma cells, histiocytes, and eosinophils
- Follicular dendritic cell proliferation outside germinal centers/around high endothelial venules (usually requires immunohistochemistry)
- Neoplastic T cell population often obscured by reactive infiltrate
- Small to medium-sized but occasionally large cells
- Abundant clear cytoplasm and irregular nuclear contour
- Often appear in clusters around high endothelial venules
- Often requires immunohistochemistry
- An early form shows hyperplastic germinal centers
- Germinal centers lack mantle zones, have irregular borders
- Subtle sprouts of follicular dendritic cells extend from germinal centers (usually requires immunohistochemistry)
- Many cases show accompanying B cell proliferation
- About 70% are EBV related
- May be polymorphic or monmorphic, immunoblastic or plasmacytic
- Diagnosis of diffuse large B cell lymphoma requires sheets of monoclonal large B cells
- Diagnosis of plasmacytoma requires sheets of monoclonal plasma cells
- Molecular evidence of B cell clonality is not sufficient for diagnosis of B cell lymphoma or plasmacytoma
- May produce a Hodgkin-like proliferation with Reed-Sternberg-like cells
- Constitutional symptoms and laboratory abnormalities common
Dita Gratzinger MD PhD
Yasodha Natkunam MD PhD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Initial posting : October 7, 2007
