Aggressive neuroblastoma with initial pulmonary metastases and kidney involvement simulating Wilms' tumor

Image-defined risk factors for nephrectomy in patients undergoing neuroblastoma resection

BACKGROUND

Although nephrectomy rates are higher in children with neuroblastoma who have image-defined risk factors and/or high-risk disease who undergo resection prior to chemotherapy, no published data outline the key radiographic and clinical characteristics associated with nephrectomy.

METHODS

With IRB approval, imaging studies of children undergoing primary resection of intraabdominal neuroblastoma between 2000 and 2014 were retrospectively reviewed. Fisher's exact and Wilcoxon rank-sum tests were used to compare categorical and continuous variables, respectively, with p-values adjusted for multiple testing using the false discovery rate approach.

RESULTS

Twenty-seven of 380 consecutive patients with CT imaging obtained prior to primary neuroblastoma resection underwent partial or total nephrectomy. On preoperative imaging, renal vessel narrowing and encasement and tumor invasion of the renal hilum, pelvis, and/or parenchyma were present significantly more frequently among patients undergoing nephrectomy. Delayed renal excretion of contrast, hydronephrosis, and tumors with MYCN amplification were also more prevalent in the nephrectomy group.

CONCLUSION

Encasement and narrowing of renal vessels, delayed excretion, and tumor invasion into the kidney, particularly pelvis and capsule invasion, are significantly associated with partial or total nephrectomy at initial neuroblastoma resection. These observations provide valuable information for surgical planning as well as presurgical discussions with families prior to neuroblastoma resection.

Imaging accuracy and incidence of Wilms' and non-Wilms' renal tumors in children

PURPOSE

The purpose of this study is to determine the actual incidence, age distribution, and preoperative imaging accuracy of non-Wilms' tumors (nWT) in children with renal masses.

METHODS

Pathologic reports from all tumor nephrectomies or open renal biopsies performed at a single institution from September 1999 to June 2005 were analyzed. Patient demographics, pathologic findings, specific imaging study descriptors, and differential diagnoses were tabulated. Accuracy of imaging studies in identifying specific tumors was calculated.

RESULTS

Ninety-two patients were identified. Sixty-eight had Wilms' tumor (WT) and 24 had an nWT. The nWT group included congenital mesoblastic nephroma (5), clear cell sarcoma (4), neuroblastoma (4), renal cell carcinoma (4), lymphoma (2), angiomyolipoma (2), teratoma (1), hemangioma (1), and renal epithelial tumor (1). When grouped by ages, the incidence of nWT was between 0% and 83%. Sensitivity, specificity, positive predictive value, and negative predictive value for computed tomography (CT) determining a diagnosis of WT were 0.92, 0.55, 0.84, and 0.73, respectively. The CT reports explicitly stated a potential diagnosis in 89% of cases, with a diagnostic accuracy of 82%.

CONCLUSIONS

Non-Wilms' tumors may represent a significant proportion of renal tumors in children, especially in children aged less than 6 months or greater than 12 years. Preoperative imaging is of limited value in differentiating these tumors. These data have significant implications for parental counseling, surgical plan, and the choice of neoadjuvant chemotherapy and argue in favor of obtaining a tissue diagnosis before instituting therapy.

Imaging in unilateral Wilms tumour

Wilms tumour is one of the most common malignancies in children, with an excellent prognosis after therapy. There is a very diverse approach to treatment according to geographical location. This variation in therapeutic attitude toward Wilms tumour, particularly between the United States and Europe, has consequences for the choice of imaging modality at diagnosis. In Europe, the International Society of Paediatric Oncology (SIOP) treatment protocol is based on chemotherapy followed by surgery. Imaging (US, CT and MRI), clinical history and examination will help predict whether the findings are consistent with Wilms tumour. Furthermore, in the UK preoperative image-guided biopsy is advised to help identify the small group of patients who, despite typical imaging features of Wilms tumour, have other types of neoplasia that require alternative management. In the United States, the National Wilms Tumor Study (NWTS) advises surgery prior to chemo- and radiotherapy. Hence imaging must provide detailed anatomical information for surgical planning. This article discusses the role of imaging at diagnosis and the relative strengths and weaknesses of the available radiological techniques. We also focus on imaging the lung for metastatic disease and the consequences (to the patient's ultimate outcome) of CT-diagnosed small pulmonary nodules and discuss the radiological diagnosis and consequences of tumour rupture present at diagnosis.

Neuroblastoma, ganglioneuroblastoma, and ganglioneuroma: radiologic-pathologic correlation

Neuroblastoma, ganglioneuroblastoma, and ganglioneuroma are tumors of the sympathetic nervous system that arise from primitive sympathogonia and are referred to collectively as neuroblastic tumors. They arise wherever sympathetic tissue exists and may be seen in the neck, posterior mediastinum, adrenal gland, retroperitoneum, and pelvis. The three tumors differ in their degree of cellular and extracellular maturation; immature tumors tend to be aggressive and occur in younger patients (median age, just under 2 years), whereas mature tumors occur in older children (median age, approximately 7 years) and tend to behave in a benign fashion. The most benign tumor is the ganglioneuroma, which is composed of gangliocytes and mature stroma. Ganglioneuroblastoma is composed of both mature gangliocytes and immature neuroblasts and has intermediate malignant potential. Neuroblastoma is the most immature, undifferentiated, and malignant tumor of the three. Neuroblastoma, however, may have a relatively benign course, even when metastatic. Thus, these neuroblastic tumors vary widely in their biologic behavior. Features such as DNA content, tumor proto-oncogenes, and catecholamine synthesis influence prognosis, and their presence or absence aids in categorizing patients as high, intermediate, or low risk. Treatment consists of surgery and, usually, chemotherapy. Despite recent advances in treatment, including bone marrow transplantation, neuroblastoma remains a relatively lethal tumor, accounting for 10% of pediatric cancers but 15% of cancer deaths in children.