Primary Effusion Lymphoma : HHV8
Immunophenotype: The neoplastic cells of primary effusion lymphoma typically have a "null" phenotype. They lack pan B-cell antigens and only rarely express T-cell antigens. The usual immunophenotypic profile is as follows: POSITIVE for: CD45, various activation antigens (HLA-DR, CD30), plasma cell-related markers (CD38, CD138, VS38c), and non-lineage antigens (EMA). The nuclei of lymphoma cells show positivity for antibody to HHV8-associated latent protein LANA1. NEGATIVE for: pan B-cell antigens (CD19, CD20, CD79a, PAX5), surface and cytoplasmic immunoglobulins (80% of cases), T-cell antigens CD2, CD3, CD5, and CD7 (rare cases are positive), CD15, and BCL6. The image shows primary effusion lymphoma which presented initially as intravascular lymphoma confined to dermal vessels. Subsequently, the patient developed pleural effusion. The patient was immunosuppressed and the lymphoma was HHV8-positive (shown here) and EBV-positive. Image courtesy of: Genevieve Crane, MD, PhD.