Misdiagnosis in Wilms tumor: Concerns on the use of preoperative chemotherapy

Abstract

INTRODUCTION & OBJECTIVES: Modern image armamentarium allows the preoperative diagnosis of Wilms tumor and the use of preoperative chemotherapy as precluded by SIOP protocols without a biopsy specimen. However, misdiagnosis is possible even with very accurate examination. This paper describes our experience with children who were preoperatively considered as having Wilms tumor and who received preoperative chemotherapy as SIOP 2001 protocol, and after delayed surgery, a different diagnosis was revealed. MATERIAL & METHODS: The charts of children admitted to our institution with diagnosis of Wilms tumor from January 2000 through December 2010 were reviewed in order to disclose all those who were submitted to preoperative chemotherapy followed by surgical removal of the tumor. The histopathological diagnosis and the subsequent treatment were reviewed. RESULTS: 81 children were admitted to our institution with the diagnosis of Wilms tumor during the analyzed period. Median age was 3.2 years (range 7 mo trough 5 years). All children presented with renal mass suggestive of Wilms tumor on abdominal ultrasonography and computerized tomography. All received preoperative chemotherapy with vincristine plus dactinomycin for four weeks, been afterwards submitted to nephrectomy. Histopathological analysis confirmed Wilms tumor in 78/81 cases (96%), but in 3/81 (4%) of the cases the diagnosis was clear cell sarcoma (1/81), multicystic kidney (1/81) and neuroblastoma (1/81). No further chemotherapy was administered to the child with multicystic kidney and the other two children were treated according to specific protocols. CONCLUSIONS: In spite of the refined image methods available in our days, misdiagnosis of Wilms tumor is still possible and it should be a concern when preoperative chemotherapy is the first line treatment.