Kidney-limited intravascular large B cell lymphoma: a distinct variant of IVLBCL?

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, it is extremely rare that lymphoma cells are localized only in the kidney. We report here a Japanese patient with kidney-limited IVLBCL. The patient presented with mild proteinuria and a good performance status without B symptoms at presentation. A renal biopsy showed large B cell neoplastic lymphocytes in the glomerular capillary lumina. Extensive systemic examinations showed no other organ involvement. The patient responded well to rituximab and anthracycline-based chemotherapy. A follow-up renal biopsy showed the disappearance of intraglomerular lymphoma cells with restoration of glomerular architecture. Within 20 months past the discontinuation of chemotherapy, no evidence of recurrence was observed. Although IVLBCL is commonly a fatal disease, favorable clinical courses were reported in some cases of IVLBCL, such as the cutaneous variant. To our knowledge, there are 8 reported cases of kidney-limited IVLBCL in the English literature. All 4 patients treated with intensive chemotherapy responded well to the treatment as our patient. We suggest that kidney-limited IVLBCL might be a distinct variant of IVLBCL.