Wilms’ Tumor

Epidemiology

Wilms tumor is the most common malignant renal tumor of childhood.

Most diagnoses between 1 and 5 years with the peak incidence at age 3.

Nearly 97% of Wilms’ tumors are sporadic, in that they occur in the absence of a heritable or congenital cause or risk factor.

A hereditary form of Wilms tumor may be associated with bilateral presentation.

Many congenital anomalies are associated with Wilms tumor, including WAGR syndrome (Wilms tumor, aniridia, genitourinary malformation, mental retardation),Beckwith-Wiedemann syndrome and some other overgrowth syndromes.

Clinical Manifestations

Abdominal Mass(often painless)

Abdominal Pain

Hypertension

Hematuria

Obstipation

Weight Loss

Hypotension

Fever

Laboratory & Imaging Studies

CBC

Liver & Renal Function Tests

Ultrasound(should be performed to evaluate the presence of renal vein or vena caval extension.)

CT

Differntial Diagnoses

Hydronephrosis

Polycystic disease of the kidney

Mesoblastic nephroma

Hamartoma

Renal cell carcinoma

Neuroblastoma

Lymphoma

Retroperitoneal rhabdomyosarcoma

Staging of Wilms’ tumor

Stage I: Tumor limited to the kidney and completely excised.

Stage II: Tumor that extends beyond the kidney but is completely excised.

No residual tumor is apparent at or beyond the margins of excision. The

tumor was biopsied, or there was local spillage of tumor confined to the

flank.

Stage III: Residual tumor confined to the abdomen. Lymph nodes in the

renal hilus, the periaortic chains, or beyond contain tumor. Diffuse peritoneal

contamination by the tumor, such as by spillage of tumor beyond the flank

before or during surgery or by tumor growth that has penetrated through

the peritoneal surface. Implants are found on the peritoneal surfaces. Tumor

extends beyond the surgical margins either microscopically or grossly. Tumor

is not completely resectable because of local infiltration into vital structures.

Stage IV: Hematogenous metastases

Stage V: Bilateral renal involvement

Treatment

Before operation, all patients suspected of having Wilms’ tumor should undergo abdominal and chest CT.

National Wilms’ Tumor Study Group (NWTSG) supports a strategy of surgery followed by chemotherapy in most instances, whereas the International Society of Paediatric Oncology (SIOP) approach is to shrink the tumor using preoperative chemotherapy.

The goal of surgery is complete removal of the tumor

Typically a transverse abdominal incision is made, and a transperitoneal approach is used.

Prognoses

In general prognoses is very good.

Prognostic factors include stage and histologic features.

Cure rates for patients with localized Wilms tumor at diagnosis are greater than 85%, whereas patients with pulmonary metastases have event-free survival rates of approximately 70% to 80%.

References

1-Schwartz’s Principles of Surgery Tenth Edition

2-NELSON ESSENTIALS OF PEDIATRICS, SEVENTH EDITION 2015

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