Wilms tumor is an embryonal cancer of the kidney composed of blastemal, stromal, and epithelial elements. Treatment may include surgical resection, chemotherapy, and radiation therapy. A chromosomal deletion of WT1 a Wilms tumor suppressor gene has been identified in some cases. Other associated genetic abnormalities include deletion of WT2 a 2nd Wilms tumor suppressor gene , loss of heterozygosity of 16q and 1p, and inactivation of the WTX gene.
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NCBI Bookshelf. Stephen W. Leslie ; Hussain Sajjad ; Patrick B. Authors Stephen W. Leslie 1 ; Hussain Sajjad 2 ; Patrick B. Murphy 3. The tumor is named after the German physician, Dr. Max Wilms, who first described it in The cause of Wilms tumor is not precisely known, but it is believed to be due to genetic alterations that deal with the normal embryological development of the genitourinary tract. Wilms is thought to develop from persistent metanephric tissue or nephrogenic rests.
Wilms tumor is the most common abdominal cancer in childhood and typically presents between ages 3 to 5 years.
There are approximately new cases in the United States every year. Girls are slightly more likely to have Wilms than boys. Ninety percent of Wilms tumors are diagnosed before six years of age with the median age of diagnosis being 3. With marked improvements in chemotherapy, the overwhelming majority of affected children now survive. Wilms tumor is associated with a number of specific syndromes including WAGR syndrome. Children with this syndrome have a specific chromosomal abnormality in the WT1 gene which is involved in both renal and gonadal development.
Another syndrome associated with Wilms is the Denys-Drash syndrome or just Drash syndrome. This includes male pseudo-hermaphroditism and progressive renal failure starting in infancy. The renal disease begins with simple proteinuria in newborns and infants which eventually progresses to nephrotic syndrome and eventually full-blown renal failure.
Ninety percent of affected individuals will eventually develop Wilms tumor. Beckwith-Wiedemann syndrome is clinically diagnosed by hemihypertrophy, pancreatic enlargement, hypertrophic kidneys, omphalocele, ear creases, macrosomia, and macroglossia.
Various other renal congenital abnormalities, such as duplication and renal ectopia, are not uncommon. A finding of perilobar nephrogenic rests in children younger than one year of age is associated with a marked increase in their risk of developing a contralateral Wilms tumor.
Classical histological features of a "favorable" Wilms tumor include a triphasic pattern of blastema, epithelial, and stromal tissues. The blastema is the most undifferentiated and possibly the most malignant component. The epithelial component can demonstrate wide variations in differentiation from an early tubular formation with primitive epithelial rosette-like structures to differentiating tubules or glomeruli-like structures, which represent nephrogenesis at different developmental stages.
The stromal component may include densely packed undifferentiated mesenchymal cells or loose cellular myxoid areas. The latter areas may be difficult to distinguish from non-tumorous stroma associated with chemotherapy-induced change. Heterologous differentiation of neoplastic stroma in the form of well-differentiated smooth or skeletal muscle cells, fat tissue, cartilage, bone, and even glial tissue is present in some cases, especially in tumors that have undergone preoperative chemotherapy.
For this reason, when Wilms tumor tissue is available, it should be checked cytogenetically for 1p and 16q deletions. Anaplasia is histologically defined as hyperchromatic, pleomorphic nuclei that are three times larger than adjacent cells and have abnormal mitotic figures. Anaplasia is associated with a poor response to treatment. Wilms tumor usually presents as an asymptomatic abdominal mass in the majority of children.
The mother may have discovered the mass during bathing the infant. Other features include:. The usual labs are not specific for Wilms tumor but need to be ordered to look for other pathologies. Routine blood work includes:    . The most common site of metastases are the lungs, so chest imaging is recommended. Metastases to bones are uncommon but ominous and typically develop later as a relapse or recurrence. It was found that the apparent diffusion coefficient ADC was substantially higher for Wilms.
This differentiation is critical as the treatments for these two tumors are different. It was suggested that a cutoff ADC value of greater than or equal to 0. While useful, this will need to be confirmed with additional studies before it can be considered a reliable indicator.
Treatment of Wilms tumor is usually nephrectomy followed by systemic chemotherapy, but some protocols initiate chemotherapy first and do the nephrectomy later.
Open surgery, however, typically provides more lymph nodes in the surgical specimen. Routine biopsies are not recommended except in unusual circumstances as a biopsy automatically increases tumor staging to Stage III. This stage requires radiation and chemotherapy. For patients without metastases who will be receiving radiation, initiation of therapy within 14 days of surgery appears to improve overall survival.
Combination chemotherapy is usually administered for more aggressive disease. Initial chemotherapy most typically includes vincristine and dactinomycin. In children with bilateral disease, immediate nephrectomy is not performed. Some experts attempt high-dose chemotherapy to kill the tumor cells and hopefully salvage the kidney. Bilateral nephrectomy immediately mandates dialysis, and so all efforts are made to salvage the kidneys. Repeat biopsies are required to determine if the tumor is responding to therapy.
Nephron sparing surgery can be performed in select cases. Hepatic veno-occlusive disease can occur in patients receiving therapy for Wilms.
Treatment for hepatic veno-occlusive disease is mainly supportive. Differential diagnosis of Wilms tumor can be tricky. While Wilms is the most common childhood renal tumor, the second most common is clear cell renal sarcoma. The prognosis is not as good as Wilms as it has higher mortality and relapse rates.
It often metastasizes to bone. Histological appearance can sometimes be similar to Wilms which can lead to a misdiagnosis. Rhabdoid renal tumors are highly malignant and are most often seen before age two and almost never in children older than five years. Congenital mesoblastic nephroma is typically found in the first year of life, most often by ultrasound. Hypertension and elevated renin levels usually accompany it. Renal cell carcinoma is rare in the pediatric age group.
However, when present, it is often at a more advanced stage than in adults. Neuroblastoma patients who are post-radiation and post-chemotherapy are at increased risk. Renal medullary carcinoma is a very aggressive and dangerous cancer that is found almost exclusively in individuals with sickle cell disease, usually trait. It tends to be highly locally-invasive and metastasizes early. Stage I indicates the tumor was completely contained within the kidney without any breaks or spillage outside the renal capsule and no vascular invasion.
Stage IV tumors are those that have spread through the vascular system to distant organs such as the lungs, liver, brain, or bones, or to distant lymph nodes. Stage V are those cases where both kidneys are involved with tumor at the time of initial diagnosis. The prognosis varies by tumor stage and histology. Radiation and chemotherapy are effective in improving survival in higher stage Wilms tumor patients, but they may also be responsible for an increased risk of secondary malignancies years later.
It will also increase the risk of osteoporosis. The addition of radiation has made a significant difference in survival compared to the use of surgery alone. Most children can live a normal life with one kidney. Of note, recent studies indicate that in females who survive there is an increased risk of developing invasive breast cancer at an early age younger than When a recurrence is found, it most often affects the lungs and is usually early; most often within two years of the initial tumor discovery.
This is thought to be due to persistent focal nephrogenic rests in the contralateral kidney. The majority of these will be found within the first 2 years after surgery. New chemotherapy drugs appear promising such as topotecan and irinotecan while stem cell transplants and targeted therapies represent promising new approaches to Wilms tumor treatment. The majority of patients first present to the pediatrician, nurse practitioner or the primary care provider.
These clinicians need to be vigilant about infants with abdominal pain as the cause may be Wilms tumor. The key to improved survival is a prompt referral to the oncologist. Because the diagnosis is often devastating to the families, a mental health nurse should provide counseling in concert with the clinician.
The pharmacist should educate the family about the chemotherapeutic medications and their adverse effects. The oncology nurse should educate the family on the surgery, the post-operative care and follow up as well as assist the clinician in monitoring the patient and provide regular follow-up. Social workers should be involved early in the care so that the patient has adequate support and does not miss out on treatment.
An interprofessional team approach is necessary for patients deemed candidates for surgery, as the recovery is prolonged and can be associated with complications. The message to the family should be consistent and realistic. Only through such an approach can client-patient relationships can be improved and hopefully translate into positive outcomes.
New approaches are being developed for those who do not initially respond well to treatment. To access free multiple choice questions on this topic, click here. This book is distributed under the terms of the Creative Commons Attribution 4. Turn recording back on. National Center for Biotechnology Information , U.
It typically occurs in early childhood years with peak incidence between 3 and 4 years of age. When part of a syndrome see below they occur even earlier, typically between 2 and 24 months of age 1. There is no recognized gender predilection, however, presentation is a little later in females 2. Clinical presentation is typically with a painless upper quadrant abdominal mass. The tumor typically arises from mesodermal precursors of the renal parenchyma metanephros. On gross inspection, these tumors are usually well circumscribed or macrolobulated. Hemorrhage and central necrosis are common findings
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Nephroblastoma in a pig
In a 6 months old, cross-bred female pig a single renal mass was observed , unilateral, of whitish colouration when cut and of about 3 cm in diameter. Histopathological examination of the mass revealed lesions compatible with a nephroblastoma. It is an embryonic renal neoplasia. In pigs and chickens its the most common primary renal neoplasm. It can be single or multiple and bilateral and can become very large, in pig it rarely metastasizes. Within the initial differential diagnosis lymphoma was also included as it is one of the most common malignancies seen in pigs and it often involves the kidneys. The neoplastic mass was sharply separated from the normal renal parenchyma asterisk by fibrous tissue capsule.
Neuroblastoma and nephroblastoma: a radiological review
Neuroblastoma NBL is the most common extra-cranial tumour in childhood. It can present as an abdominal mass, but is usually metastatic at diagnosis so the symptomatology can be varied. Nephroblastoma, also more commonly known as a Wilms tumour, is the commonest renal tumour in childhood and more typically presents as abdominal pathology with few constitutional symptoms, although rarely haematuria can be a presenting feature. The pathophysiology and clinical aspects of both tumours including associated risk factors and pathologies are discussed. Oncogenetics and chromosomal abnormalities are increasingly recognised as important prognostic indicators and their impact on initial management is considered.