Wilms' tumor overview
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
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Overview
Wilms' tumor or nephroblastoma is a tumor of the kidneys that typically occurs in children, rarely in adults. Its common name is an eponym, referring to Dr. Max Wilms, the German surgeon (1867-1918) who first described this kind of tumor.[1]
It is made up of blastemal, epithelial and mesenchymal components.
It is the fourth most commonly seen malignant tumor in children in the U. S.
Approximately 500 cases are diagnosed in the U.S. annually. The majority (75%) occur in otherwise normal children; a minority (25%) is associated with other developmental abnormalities. It is highly responsive to treatment, with about 90% of patients surviving at least five years.
Historical Perspective
Wilms' tumor was first described by Dr. Osler in 1814.
Pathophysiology
The tumour typically arises from mesodermal precursors of the renal parenchyma (metanephros). On microscopic histopathological analysis, tubules, solid sheets of small round cells, and stroma are characteristic findings of wilms' tumor. Development of wilms' tumor is the result of multiple genetic mutations.
Causes
Wilms' tumor may be caused by either genetic mutations or chromosomal alterations.
Wilms' tumor differentiating from other disease
Wilms' tumor must be differentiated from neuroblastoma, cystic nephroma, and angiomyolipoma.
Epidemiology and Demographics
Wilms' tumors are the most common paediatic renal mass. The incidence of Wilms' tumor is estimated to be 0.71 cases per 100,000 children younger than 15 years. There is no significant gender predilection among unilateral cases, but the male to female ratio in bilateral cases is 0.60:1.00. It typically occurs in early childhood with peak incidence between 3 and 4 years of age. Asian individuals are less likely to develop Wilms' tumor.
Risk factors
The risk factors of wilms' tumor include family history, congenital anomalies, and associated syndromes.
Screening
Children predisposed to wilms tumor should be screened earlier. The frequency of malformations observed in patients with Wilms tumor underlines the need for genetic counseling, molecular and genetic explorations, and follow-up.
Natural history, Complications and Prognosis
The complications of wilms' tumor include metastasis, high blood pressure, and kidney damage. Prognosis is generally good. The 5-year survival rate for Wilms tumor in children is around 90%, whereas older patients suffer worse outcome. The overall 5-year survival rate is approximately 63% for patients aged 10 to 16 years. Also, according to the different stage, anaplastic tumors have the relatively poorer outcome.
Staging
There are 5 stages of wilms' tumor based on both the results of the imaging studies and the surgical and pathologic findings at nephrectomy.
History and Symptoms
The common symptoms of wilms' tumor include swelling, abdominal pain, fever, hypertension, and hypercalcemia.
Physical Examination
On abdominal examination a painless mass may be palpated in the flank.
CT
CT scan may be helpful in the diagnosis of wilms' tumor.
MRI
MRI may be helpful in the diagnosis of wilms' tumor.
Ultrasound
Ultrasound may be helpful in the diagnosis of wilms' tumor.
Other Diagnostic Studies
18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)-CT and biopsy may be helpful in the diagnosis of wilms' tumor.
Medical therapy
The predominant therapy for wilms' tumor is surgical resection. Adjunctive chemotherapy and radiation may be required.
Surgery
Surgery is the mainstay of treatment for wilms' tumor.