Extensive tumor involvement of renal sinus soft tissue.In Stage III (20% of cases), 1 or more of the following criteria must be met:
Inoperable primary tumor. Lymph node metastasis. Tumor is present at surgical margins. Tumor spillage involving peritoneal surfaces either before or during surgery, or transected tumor thrombus. The tumor has been biopsied prior to removal or there is local spillage of tumor during surgery, confined to the flank.Stage IV (10% of cases) Wilms tumor is defined by the presence of hematogenous metastases (lung, liver, bone, or brain), or lymph node metastases outside the abdominopelvic region.Stage V (5% of cases) Wilms tumor is defined by bilateral renal involvement at the time of initial diagnosis. For patients with bilateral involvement, an attempt should be made to stage each side according to the above criteria (stage I to III) on the basis of extent of disease prior to biopsy. Treatment and prognosis
The overall 5-year survival is estimated to be approximately 90%, but for individuals the prognosis is highly dependent on individual staging and treatment. Early removal tends to promote positive outcomes. Tumor-specific loss-of-heterozygosity (LOH) for chromosomes 1p and 16q identifies a subset of Wilms tumor patients who have a significantly increased risk of relapse and death. LOH for these chromosomal regions can now be used as an independent prognostic factor together with disease stage to target intensity of treatment to risk of treatment failure.
In particular, cases of bilateral Wilms tumor, as well as cases of Wilms tumor derived from certain genetic syndromes such as Denys-Drash syndrome, are strongly associated with nephrogenic rests. Most nephroblastomas are on one side of the body only and are found on both sides in less than 5% of cases, although people with Denys-Drash syndrome mostly have bilateral or multiple tumors. They tend to be encapsulated and vascularized tumors that do not cross the midline of the abdomen. In cases of metastasis it is usually to the lung. A rupture of Wilms tumor puts the patient at risk of bleeding and peritoneal dissemination of the tumor. In such cases, surgical intervention by a surgeon who is experienced in the removal of such a fragile tumor is imperative.Pathologically, a triphasic nephroblastoma comprises three elements:
blastema
mesenchyme (stroma)
epitheliumWilms tumor is a malignant tumor containing metanephric blastema, stromal and epithelial derivatives. Characteristic is the presence of abortive tubules and glomeruli surrounded by a spindled cell stroma. The stroma may include striated muscle, cartilage, bone, fat tissue, and fibrous tissue.