Neonatal neuroblastoma 4s with diffuse liver metastases (Pepper syndrome) without an adrenal/extraadrenal primary identified on imaging.

We report the imaging appearances of a case of pathologically proven, neonatal neuroblastoma 4S with diffuse hepatic metastatic involvement at presentation. Patient had an abnormal appearing liver both by ultrasound and MR. There was no evidence for associated adrenal tumor by imaging. Lack of an associated adrenal mass led to initial misinterpretation of diffuse hepatic accumulation of MIBG seen with radionuclide scintigraphy. To the best our knowledge, this is the first report of metastatic neonatal 4S neuroblastoma without an adrenal (or extra-adrenal) primary identified either on pre- or post-natal imaging.