Kidney lymphoma is a form of cancer from the immune system’s lymphocytes that affects one or both kidneys. Most cases occur when lymphoma from another part of the body spreads to the kidneys, and it is most often a type of non-Hodgkin’s lymphoma. In rare instances, the lymphoma can start within the kidney itself. This cancer’s presence in the renal system requires diagnostic and management approaches that are distinct from other kidney tumors.
Primary vs. Secondary Kidney Lymphoma
Lymphoma in the kidneys is classified as either primary or secondary based on its origin. Primary renal lymphoma (PRL) is an exceptionally rare diagnosis where the lymphoma is confined to the kidneys with no evidence of disease elsewhere. This form accounts for less than one percent of all lymphomas that appear outside the lymph nodes. The development of PRL is not fully understood, as kidneys do not contain lymphoid tissue.
Secondary renal lymphoma (SRL) is far more common. This occurs when a lymphoma originating in the lymph nodes, bone marrow, or spleen spreads to the kidneys. Kidney involvement is often seen in advanced stages of systemic non-Hodgkin’s lymphoma. Autopsy studies show the kidneys are affected in a significant percentage of individuals with widespread lymphoma, though it is detected less frequently on imaging scans during their lifetime.
Associated Symptoms and Signs
Symptoms of kidney lymphoma can be directly related to the kidneys or systemic, affecting the whole body. Kidney-specific signs include pain in the flank (the area between the ribs and hip), a palpable lump in the abdomen, or hematuria (blood in the urine).
Patients also experience general symptoms characteristic of lymphomas. These are sometimes called “B” symptoms and can accompany both primary and secondary kidney lymphoma.
- Unexplained fevers
- Drenching night sweats
- Significant, unintentional weight loss
- Pervasive fatigue
- A swollen stomach
- Loss of appetite
The Diagnostic Process
Diagnosing kidney lymphoma is a multi-step process. Initial evaluations include blood and urine tests. Blood work helps assess kidney function by measuring creatinine levels and can reveal abnormal blood cell counts, while urinalysis is used to detect blood or other irregularities in the urine.
If these tests suggest a problem, imaging studies are ordered for a detailed view of the kidneys. A Computed Tomography (CT) scan is frequently used to identify the size and number of masses, which in lymphoma often appear as multiple nodules. Magnetic Resonance Imaging (MRI) can provide additional detail, and a Positron Emission Tomography (PET) scan helps detect lymphoma cells throughout the body to determine if the cancer is primary or secondary.
While imaging can strongly suggest lymphoma, a definitive diagnosis requires a biopsy. In this procedure, a small sample of the kidney tumor is removed with a needle and examined by a pathologist. This analysis confirms the presence and specific subtype of lymphoma, which is important because its treatment differs from other kidney cancers.
Treatment Approaches
The management of kidney lymphoma centers on systemic therapies designed to treat cancer throughout the body, differing from the surgical focus for other renal tumors. Chemotherapy is the primary treatment for most cases. A common and effective drug combination is a regimen known as R-CHOP, which includes rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone. This approach targets and destroys cancerous lymphoma cells systemically.
Surgery to remove the kidney (nephrectomy) is not a first-line treatment. Because lymphoma is a systemic disease, even when it appears localized, removing the kidney would not address cancer cells elsewhere in the body. Surgery might only be considered to manage a severe complication.
Other treatments may be used with or as an alternative to chemotherapy. Immunotherapy helps the body’s own immune system fight the cancer, and targeted therapies focus on specific vulnerabilities in cancer cells. Radiation therapy also has a role but is reserved for specific circumstances, such as targeting a localized area causing significant symptoms.
Prognosis and Follow-Up Care
The outlook for an individual with kidney lymphoma depends on several factors, including whether the lymphoma is primary or secondary, its specific subtype, the stage at diagnosis, and the person’s overall health. How well the cancer responds to initial treatment also plays a large part in the long-term prognosis. Because primary renal lymphoma is so rare, most outcome data is based on the more common secondary form.
Following the completion of initial treatment, long-term follow-up care is standard. This involves regular appointments with an oncology team to monitor for any signs of the cancer returning. These check-ups often include physical exams, blood tests, and periodic imaging scans, such as CT or PET scans, to ensure any potential recurrence is detected early.