Lymphomatoid Granulomatosis : Immunophenotype

Comments:
The large atypical transformed cells in lymphomatoid granulomatosis are B cells which express CD20, CD79, and PAX5. They may be positive for CD30 but are CD15 negative (helpful in distinction from classical Hodgkin lymphoma). CD56 and CD57 are also negative.

A variable number of large atypical cells are EBV-positive, which is harder to demonstrate in cutaneous lesions than in pulmonary lesions. In-situ hybridization for EBV-coded RNA (EBER) is superior to immunohistochemistry for latent membrane protein 1 (LMP1) for detecting EBV (shown here).

The small reactive lymphocytes that make up the bulk of background cells are CD3+ T-cells, predominantly of CD4+ helper subtype.

Image courtesy of: Univ. of Michigan Dept. of Pathology; used with permission