Image 8 of 12



Image Description

Immunophenotype of T-cell/histiocyte-rich large B-cell lymphoma:

Neoplastic large cells: They express pan B-cell markers (CD20 (shown here), CD22, CD79a, & PAX5) and show variable light chain restriction. CD15, CD30, CD5, and CD10 are usually negative. They express BCL2 (40% of cases) and BCL6 (40% to 60% of cases). EMA is positive in about 30% of cases. EBV is negative.

Background cells: The small lymphocytes that make up the bulk of the lesion are reactive T-cells of cytotoxic type that express CD3, CD8, and TIA-1. There are variable numbers of CD68+ and CD163+ histiocytes. Small reactive B-cells are rare.

The neoplastic large B-cells should not be surrounded by rosettes of follicular T-cells (CD57+, PD-1+) or meshwork of CD21-positive follicular dendritic cells. These features are seen in nodular lymphocyte-predominant Hodgkin lymphoma.

Image 8 of 12