Intravascular large B-cell lymphoma with a high titer of proteinase-3-anti-neutrophil cytoplasmic antibody mimicking granulomatosis with polyangiitis

Abstract

A 63-year-old man presented with fever, sinusitis, otitis, and high titers of proteinase-3 anti-neutrophil cytoplasmic antibody (PR3-ANCA). Granulomatosis with polyangiitis (GPA) was first suspected. However, nasal mucosa and skin biopsies revealed the presence of intravascular large B-cell lymphoma (IVLBCL). We present a rare case of IVLBCL with a high titer of PR3-ANCA mimicking GPA.