Primary renal lymphoma: A population‐based analysis using the SEER program (1973‐2015)

OBJECTIVE: Primary renal lymphoma (PRL) is defined as a non‐Hodgkin lymphoma (NHL) restricted to kidneys without extensive nodal disease. The literature on epidemiology and outcome in PRL is limited to case reports and small case series. METHODS: We utilized Surveillance, Epidemiology, and End Result database (1984‐2015) to study the demographic, clinical, and pathological characteristics of PRL. We conducted analysis to assess factors associated with overall survival (OS) and cause‐specific survival (CSS). RESULTS: A total of 599 (0.17% of all NHL) patients were eligible for the study. The age‐adjusted incidence was 0.035/100,000 population and is increasing. The median age was 72 years, and most of the patients were Caucasians and were males. Most of the patients had unilateral tumors, and diffuse large B‐cell lymphoma (DLBCL) was the most common histologic type. The median OS was 112 months, while median CSS was not reached. Age ≥ 60 years was the strongest independent risk factor for worse OS and CSS, while non‐DLBCL histology was associated with better OS and CSS. DISCUSSION: Primary renal lymphoma is a rare lymphoma with increasing incidence in more recent years. In this study, we describe demographic, clinical, and pathological characteristics of PRL and factors affecting survival among these patients.