Primary renal lymphoma in an immunocompetent patient.

Renal lymphoma is rarely primary, but its diagnosis is critical because it requires specialized medical treatment. We present the case of a 59-year-old man who was admitted to the hospital for a painful left renal mass revealed by isolated chronic low back pain. A clinical examination revealed left lumbar tenderness. A non-lymphoma Hodgkin's type B was discovered during a renal biopsy. As part of the extension workup, a PET scan was performed, which revealed no secondary location, and the patient underwent chemotherapy. Following the start of chemotherapy, a complete remission was observed, as well as a reduction in the size of the kidney.