|History: 7-year-old female with right nephrectomy for Wilms tumor in January 2007 now presenting with persistent right leg lesion and pain. Rule out metastatic disease.|
Right pretibial soft tissue mass is hypermetabolic by positron emission tomography. In conjunction with prior MRI, this almost certainly represents granuloma annulare. No evidence of metastatic disease.
Clinical Utility: 18F-FDG-PET/PET-CT shows promise for identifying metastatic disease, differentiating benign nephrogenic rests and nephroblastomatosis from Wilms' tumor, directing biopsy sites, and contributing to surgical planning (SC Kaste, JS Dome -Practical Pediatric PET Imaging, 2006, pages 256-257).