Wilms tumor or nephroblastoma is the most common renal cancer in children. This malignant tumor accounts for more than 95% of all kidney tumors in the pediatric age group and typically arises in a single kidney. Named after the German physician, Dr. Max Wilms, who first described it in 1899, Wilms tumor is generally found in children under the age of 5 with the median age at diagnosis of 3.5 years. The highest rates of this cancer are reported in children of black African descent and the lowest in those of Asian descent, suggesting that genetic factors may play an essential role in its etiology. Survival for patients with Wilms tumor once <30% is currently greater than 90%, making it one of the astonishing successes of modern medicine. This excellent outcome is a result of intense collaborative efforts among pediatric surgeons, pathologists, radiologists, and oncologists.CASE SUMMARYA toddler with severe abdominal pain and palpable abnormality in the right upper quadrant extending to the right lower quadrant was brought in for an imaging evaluation.IMAGING FINDINGSUltrasound revealed a large heterogeneous vascularized mass occupying the right upper and lower quadrants of the abdomen, measuring 13.4 cm. Recommended CT confirmed the presence of a very large heterogeneously enhancing right suprarenal abdominal tumor, displacing vascular structures and adjacent anatomy. Imaging findings suggest Wilms tumor with the leading secondary differential diagnosis of neuroblastoma.FINAL DIAGNOSIS: Wilms tumor.EPIGASTRIC AREA TRVRUQ/EPIGASTRIC AREA TRV30
he exact cause of the Wilms tumor is unknown. It is believed to result from genetic mutations that deal with the normal embryological development of the genitourinary tract. Children with nephroblastoma typically present with an asymptomatic abdominal mass discovered by a parent or a relative. Abdominal pain is the most common initial symptom in the symptomatic presentation, followed by hypertension and hematuria. Occasionally, a child may present with a rapidly enlarging abdominal mass, anemia, and fever. Such presentation is common in children with a subcapsular hemorrhage within the tumor that induces these symptoms.
Other associated symptoms include urinary tract infections, varicocele, and dyspnea or tachypnea if the patient has lung metastases.CTSAGRT KIDNEY AREA SAGRT KIDNEY AREA TRVThe large heterogeneously hypoechoic solid mass arising from the right kidney is Wilms tumor.32
Abdominal ultrasonography is usually the initial study in the work-up of a child with suspected intraabdominal mass. Ultrasound evaluation is easily obtained, requires no sedation, and can most often confirm the presence of a mass, organ of origin (intrarenal or extrarenal), and the nature of a mass (cystic or solid). Sonographically, Wilms tumor most often presents as a large heterogeneous solid mass displacing adjacent anatomy. Occasionally it may have cystic components often representing intralesional necrosis. The extension of tumor thrombus in renal vein and IVC is common in advanced disease and can be evaluated using Doppler ultrasound. Although nephroblastoma most commonly arises in a single kidney, synchronous disease in both kidneys occurs in approximately 5% of children.
After the initial sonographic assessment, abdominal CT or MRI is often used to evaluate the extent of the renal mass identified on ultrasound and determine whether metastatic disease is present. Chest CT is commonly performed to assess for pulmonary nodules, which is the most common site of metastatic spread. The cancer stage is determined before surgery, however confirming the diagnosis of Wilms tumor and complete staging occurs after surgery. A biopsy is not routinely recommended before the surgical exploration to avoid the potential spread of malignancy. Appropriate postoperative treatment regimens are determined based on histology and molecular markers of the surgical specimen.
Wilms tumor treatment approach varies depending on cancer stage, presence of metastases, patient’s age, tumor weight, histology, biologic risk factors, and clinical response to therapy. The treatment in most patients involves a combination of surgery (usually nephrectomy) and systemic chemotherapy. Surgery maintains an integral role in the treatment of Wilms tumor; however, the improved outcome for this malignancy during the last century is assigned mainly to advances in chemotherapy. Survival for patients with Wilms tumor is currently greater than 90%, making it one of the incredible successes of modern medicine.39-43RT KIDNEY AREA TRVCTTRVThe large heterogeneously hypoechoic solid mass arising from the right kidney is Wilms tumor.33
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