Lymphomatoid Granulomatosis : Introduction

Lymphomatoid granulomatosis (LG) is a rare extranodal EBV-driven B-cell lymphoproliferative disorder primarily involving the lungs. One-third of cases show extrapulmonary lesions (primarily skin and CNS). It is an angiocentric and an angiodestructive process with transmural infiltration of the vessel walls by mononuclear cells and large areas of necrosis. The polymorphous infiltrate contains atypical clonal EBV-positive B-cells in a polymorphous background rich in reactive T cells. The large atypical cells express B-cell markers (CD20, CD79, and PAX5). They may be positive for CD30; but CD15, CD56, and CD57 are negative. Some of the large atypical cells show EBV, which is best demonstrated by in-situ hybridization for EBV-coded RNA (EBER) for latent membrane protein 1 (LMP1). The small reactive lymphocytes are CD3+ T-cells, predominantly of CD4+ helper subtype. The prognosis is poor with a median survival of 2 years. Low-grade lesions are treated by immunomodulation therapy (interferon-alpha). High-grade lesions require a combination of aggressive chemotherapy and immunotherapy. References:Jaffe, E. S. et al (2017). Hematopathology - Second Edition. Philadelphia, PA. Elsevier; p. 554-556. Burger, P. C. et al (2012). Diagnostic Pathology - Neuropathology. Amirsys Publishing Inc., Salt Lake City, Utah. Dunleavy K, Roschewski M, and Wilson WH. Lymphomatoid Granulomatosis and Other Epstein-Barr Virus Associated Lymphoproliferative Processes. Curr Hematol Malig Rep. 2012 September; 7(3):208-215.