Coexistence of Diffuse Large B-Cell Lymphoma With Chronic Tubulointerstitial Nephritis: A Case Review and Pathophysiology.

There is an association between lymphomas and kidney disease with renal abnormalities found both in patients with direct infiltration by lymphoma as well as in patients without gross or microscopic evidence of renal involvement. Multiple mechanisms to explain the link between lymphomas and renal disease have been proposed, ranging from direct renal metastasis by the lymphoma to chemokine signaling pathways. In addition, there is a correlation between certain genetic mutations and an increased risk of lymphoma metastasizing to other organs. We present a case of a 41-year-old male who passed away due to end-stage kidney disease and was found on autopsy to have chronic tubulointerstitial nephritis and diffuse large B-cell lymphoma (DLBCL) without direct renal involvement by the lymphoma. The patient had been previously healthy with no significant prior medical history, NSAID, or other contributory medication use of note with the only presenting symptom being renal failure. Only upon autopsy was DLBCL discovered throughout the abdomen with no direct lymphoma involvement evident in the kidneys. To the author's knowledge, this is one of the few reported cases of DLBCL in English literature without renal infiltration in which the presenting symptom and cause of death was renal dysfunction. Several mechanisms have been theorized for how lymphomas can lead to kidney damage without direct metastasizes; however, more research still needs to be done to better understand the underlying etiology. Given the rarity and the lack of direct infiltration of lymphoma into the kidneys in this patient, we hope reporting this case will allow further advancements in this field of study as well as more comprehensive management.