Deciphering the association between biopsy-confirmed systemic small vessel vasculitis and Epstein-Barr virus-positive polymorphic B-cell lymphoproliferation.

The Epstein-Barr virus (EBV) is associated with various lymphoproliferative disorders (LPD). Additionally, EBV infection has correlated with diverse autoimmune diseases. However, the association between EBV and systemic small vessel vasculitis (SVV) remains controversial. Here, we report a case of SVV with pauci-immune glomerulonephritis accompanied by an EBV-positive polymorphic B-cell LPD, not otherwise specified. The intricate distinction between EBV-positive B-cell LPD and SVV was difficult, as both diseases demonstrated similar clinical presentations. Lymph node and kidney biopsies facilitated the accurate diagnosis of these two conditions. The administration of high-dose prednisolone, combined with rituximab, proved efficacious, with no instances of relapse over the subsequent 2-year period. This case indicates an association between EBV-positive B-cell LPD and SVV. The diligent execution of biopsies is a crucial diagnostic and interpretive strategy, generating precise comprehension of this condition and guiding its appropriate therapeutic management.