Mimicker of Osteoblastic Skeletal Metastasis on 18 F-FDG PET/CT Scan in a Case of Primary Mediastinal Germ Cell Tumor.

Primary mediastinal germ cell tumors are uncommon tumors, of which the nonseminomatous type is more likely to metastasize than the seminomatous type. Primary mediastinal germ cell tumors may also present with superior vena cava obstruction. Here, we present this case of primary mediastinal germ cell tumor with superior vena cava obstruction causing dilatation of collaterals in dorsal intravertebral venous plexus, which strongly mimics sclerotic skeletal lesions/metastasis on a Contrast-enhanced CT scan and also appears FDG avid on PET scan. Herein, we can differentiate the two by just a simple review of plain CT scan image.