AVOIDING MISDIAGNOSING NEUROBLASTOMA AS WILMS TUMOR

Purpose: Although occasionally difficult, distinguishing abdominal neuroblastoma (NBL) from Wilms tumor (WT) at presentation is important, as surgical management differs significantly. We reviewed our 20-year experience (1987-2006) treating patients with NBL, focusing on those with an initial diagnosis of WT, to determine presenting features that would have suggested the correct preoperative diagnosis. Methods: Retrospective case cohort study reviewing charts and imaging of patients with NBL initially diagnosed clinically with WT. Preoperative symptoms, laboratory studies, and imaging were evaluated. Similar variables were assessed in the 20 patients with WT most recently treated at our institution. Results: Nine patients with NBL were identified as those who had an exploratory laparotomy with a preoperative diagnosis of WT; 8 underwent nephrectomy at exploration. Children with NBL had symptoms such as fever and weight loss at presentation (67%) more often than patients with WT (20%). Preoperative computed tomography demonstrated intratumoral calcifications, vascular encasement, or both in 78% of patients with NBL but were never seen in WT patients. Of interest, preoperative urinary catecholamines were elevated in 5 patients ultimately diagnosed with NBL. Conclusion: Although NBL can be mistaken for WT at presentation, the presence of constitutional symptoms, or intratumoral calcification or vascular encasement on preoperative imaging should heighten suspicion for NBL. In addition, laboratory evaluation, including urinary catecholamines, should be completed before surgery when the etiology of an abdominal tumor is uncertain.