Round Cell Liposarcoma Presenting as an FDG-Positive Primary With an FDG-Negative Retroperitoneal Metastasis

• DOI: 10.1097/rlu.0b013e3182335e32
• Publication Date: 2011-11-05T10:56:38Z
• Authors: Rajan Rakheja; William Makis; Ayoub Nahal; Yazan Z. Alabed; Gad Abikhzer; Stephan Probst; Marc Hickeson
• Keywords: Adult; Male; Liposarcoma; Multimodal Imaging; Diagnosis, Differential; 03 medical and health sciences; 0302 clinical medicine; Fluorodeoxyglucose F18; Positron-Emission Tomography; Humans; Retroperitoneal Neoplasms; Tomography, X-Ray Computed

A 34-year-old man, who presented with a 10-month history of an enlarging right ankle mass histologically proven to be round cell/myxoid liposarcoma, was referred for F-18 FDG PET/CT scan, which showed heterogenous FDG-positive primary in the and 1.2-cm, FDG-negative, retroperitoneal lipid-attenuating nodule. On follow-up scan done 1 year later, nodules had grown into 11-cm mass, became subsequently confirmed liposarcoma metastasis. We present imaging characteristics this highly unusual case possible histologic explanation false-negative metastasis on staging scan.