Lymphomatoid granulomatosis.

Lymphomatoid granulomatosis (LYG) is a very rare Epstein-Barr virus (EBV)-driven lymphoproliferative disease. The atypical lymphoid cells directly accumulate within affected tissues and clinically present in the form of infiltrative lesions. It is usually a progressive disorder that virtually always involves the lung and characteristically presents as bilateral pulmonary nodules. Other commonly affected organ systems include the skin, central nervous system, and kidneys. The rareness of LYG in conjunction with its nonspecific presentation contributes to delays in diagnosis in many situations. Pathologically, it is characterized by the presence of an angiocentric and angiodestructive accumulation of varying numbers of T cells with varying numbers of atypical clonal EBV-positive B cells in a polymorphous inflammatory background. It can be subclassified using a grading system based on the number of EBV-positive large B-cell malignant cells, which is critical in selecting appropriate management strategies. Lower-grade LYG occasionally undergoes spontaneous remission and is best managed with strategies designed to enhance the host's underlying immune system, whereas high-grade LYG is best managed by combination chemoimmunotherapy but has inferior outcomes. Lymphomatoid granulomatosis can lead to progressive pulmonary failure, central nervous system disease, or progression to overt EBV-positive lymphoma without appropriate recognition and management. Improvements in the modern understanding of the biology of LYG, particularly the precise role of EBV in its pathogenesis, offer promise in the development of improved management strategies.