Intrarenal neuroblastoma mimics Wilms' tumor

Abstract

This work reports the case history of a child with intrarenal neuroblastoma, initially diagnosed as Wilms' tumor. The patient, a one year and three months old girl, presented a hard abdominal mass on the left flank that extended to the mesogastric region, plus fever and paleness. The ultrasound of the entire abdomen revealed an intrarenal mass. Biopsy with fine needle in many points of the tumor revealed Wilms' tumor. The scarcety of the material, however, made immunohistoquemistry impossible at that moment. Because of the child's severe condition the SIOP protocol was started. As no clinical response was observed, an exploratory laparatomy was indicated with partial resection of the tumor and bone marrow aspiration (MO). The histopathologic study revealed a malignant neoplasia of small cells, poorly differentiated. IHQ was negative for WT-1 and positive for NB-84, synaptofisin, cromogranine. N-myc amplification was observed by molecular biology. The bone marrow aspiration identified matastatic small round cells infiltration. Intrarenal neuroblastoma is a rare entity that clinically and radiographically resembles Wilms' tumor. The objective of this case report is to show the importance of immunohistochemical and molecular analysis in the diagnosis of intrarenal neuroblastoma.