Wilms tumor / renal tumors

Wilms Tumor / Renal Tumors

Wilms tumor is the most common type of kidney cancer found in children. Also known as nephroblastoma, this cancer usually affects children under the age of 5 and often presents as a painless swelling or mass in the abdomen. In rare cases, other types of renal tumors can occur in pediatric patients, including clear cell sarcoma and rhabdoid tumor of the kidney. Prompt diagnosis and treatment are essential to achieving positive outcomes, which are excellent in most cases with early intervention.

Causes and Risk Factors

The exact cause of Wilms tumor is unknown, but it is linked to abnormal kidney cell development during fetal growth. Most cases occur sporadically, though some are associated with genetic syndromes such as WAGR, Denys-Drash, or Beckwith-Wiedemann syndrome. Children with a family history of Wilms tumor or certain congenital abnormalities may be at increased risk.

Symptoms

Wilms tumor often grows quite large before symptoms appear. Common signs include:

• A firm, non-tender abdominal mass
• Abdominal pain or swelling
• Fever
• Blood in the urine (hematuria)
• High blood pressure

In many cases, the tumor is discovered during a routine checkup or by a caregiver noticing a lump in the child’s belly.

Diagnosis

Diagnostic evaluation begins with a physical exam, followed by imaging studies such as abdominal ultrasound, CT scan, or MRI. Blood and urine tests are used to assess kidney function and identify potential spread of the tumor. A biopsy may be performed to confirm the diagnosis, though this is sometimes deferred until after surgical removal of the tumor.

Treatment

Wilms tumor treatment typically involves a combination of surgery, chemotherapy, and in some cases, radiation therapy. The primary surgical procedure is a nephrectomy—removal of the affected kidney. If the tumor is found in both kidneys (bilateral Wilms tumor), partial nephrectomies may be performed to preserve kidney function. Most children respond very well to therapy, and survival rates are high when the tumor is detected early.

Follow-Up and Prognosis

Long-term prognosis depends on the tumor stage and histology. Favorable-histology Wilms tumors have a cure rate of over 90% in early stages. Ongoing follow-up includes imaging, kidney function monitoring, and support for any late effects of chemotherapy or radiation. Lifelong surveillance may be needed for children with underlying syndromes or bilateral involvement.