Mild proteinuria in a patient with glomerularlimited intravascular large B-cell lymphoma

Intravascular large B-cell lymphoma (IVLBCL) is a rare type of non- Hodgkin lymphoma characterized by a disseminated intravascular proliferation of tumor cells in the lumina of small vessels. Although the kidney is one of the target organs of IVLBCL, lymphoma cells that localize only in glomeruli are extremely rare. We report a 55-year-old Chinese patient diagnosed as glomerular-limited IVLBCL by percutaneous renal biopsy. The patient was referred to our institution for further examination of mild proteinuria and anemia without lymphoma symptoms. He had daily urinary excretion of 0.65 g proteins with normal renal function. Percutaneous renal biopsy showed that lymphoid cell accumulation was encircled within the glomerular capillary lumina only in certain glomeruli, resulting in marked obstruction of capillary structure. However, almost all of the peritubular capillary and tubulointerstitium were intact. Immunohistochemical analysis confirmed the diagnosis of intravascular large B-cell lymphoma. Extensive systemic examinations showed no other organ involvement. With these characteristic changes, glomerularlimited IVLBCL were considered as an exceptional renal manifestation of intravascular lymphoma diagnosised by percutaneous renal biopsy.