Pediatric Extra-Renal Nephroblastoma (Wilms’ Tumor): A Systematic Case-Based Review

Abstract

Wilms Tumor (WT) is one of the most common renal tumors in the pediatric population. Occasionally, WT can primarily develop outside the kidneys (Extra-Renal Wilms Tumor, ERWT). Most pediatric ERWTs develop in the abdominal cavity and pelvis, whereas the occurrence of this tumor in other extra-renal sites represents a minor part of ERWT cases. In addition to describing a case of spinal ERWT (associated with spinal dysraphism) in a 4-year boy (to add a further clinical experience on this very rare pediatric tumor), we performed a case-based systematic literature review on pediatric ERWT. We retrieved 72 papers providing enough information on the diagnosis, treatment, and outcomes of 98 ERWT pediatric patients. Our research highlighted that a multimodal approach involving both chemotherapy and radiotherapy, after partial or complete tumor resection in most cases, was typically used, but there is no standardized therapeutic approach for this pediatric malignancy. However, this tumor may be potentially treated with a better success rate if the diagnostic confirmation is not delayed, the mass can be totally resected, and an appropriate and, possibly, tailored multimodal treatment can be promptly established. In this regard, an international agreement on a unique staging system for (pediatric) ERWT is definitely needed, as well as the development of international research, which may be able to gather several children diagnosed with ERWT and, possibly, lead to clinical trials which should also include developing countries.

The impact of the route to diagnosis in nephroblastoma

“…In a retrospective study from a single center in India, age, the education of the mother and the cancer type were found to be the most important factors predicting the time to diagnosis and treatment 24 . In summary, in low and middle income countries, several diagnostic barriers can impair health care in general 1 leading to later diagnosis.…”

“…Although nephroblastoma or Wilms tumor (WT) is rare, it is the most common childhood kidney tumor and can even seldomly arise in extra-renal sites without any association to the kidney. 1 For more than 50 years this tumor has been treated in prospective multicenter and randomized trials by the International Society of Pediatric Oncology (SIOP), the Childrens' Oncology Group (COG), and others. 2,3 Outcome has improved over time with a long-term survival of 90% today.…”

Malignant Extrarenal Rhabdoid tumor derived from the greater omentum: A case report and literature review

“…For differential diagnosis, histologic and IHC findings should be kept in mind and Wilms' tumor, GIST, sarcoma, malignant melanoma, and lymphoma should be considered. 22 , 23 , 24 Because of the aggressive clinical behavior and poor prognosis of the disease, its differential diagnosis should be made, however, at present, the differential diagnosis is a great challenge, which is worthy of further exploration.…”

Extrarenal Wilms tumor mimicking funicular hydrocele

“…There are about a hundred cases of ERWT presented in literature. The most common locations of ERWT are the retroperitoneum, inguinal area, lumbosacral and pelvic region, female genital organs (including the uterus, cervix, vagina, and ovaries), mediastinum and chest wall, and spermatic cord and paratesticular region (1,(3)(4)(5)(6)(7)(8)(9)(10)(11)(12).…”