title: Rare case of conus medullaris syndrome from a metastatic yolk sac tumor originating from the mediastinum of an adult male: a case report and review of the literature.
abstract: BACKGROUND
  Yolk sac tumors (YST) are malignant neoplasms. They are a subtype of germ cell tumors and typically originate in the gonads although extragonadal origins of such tumors have been described. Yolk sac tumors are commonly found in the gonads of infants and children and are extremely rare in adults. The goal of this case report is to describe the clinical presentation of a rare case of metastatic extragonadal yolk sac tumor originating from the mediastinum and causing an acute conus medullaris syndrome in an adult male.
  
  
  METHODS
  A 47-year old male presented to our emergency department with a one-day history of bilateral lower extremity weakness, urinary retention and bowel incontinence. Imaging revealed a destructive lesion and a burst fracture of the first lumbar vertebral body (L1) with severe spinal canal stenosis. An urgent spinal decompression and fusion was performed. Oncologic workup revealed a yolk sac tumor originating from the mediastinum.
  
  
  RESULTS
  His neurologic function, including motor strength, bowel and bladder function improved in the postoperative period. Chemotherapy regimen of ifosfamide, etoposide and cisplatin was administered and radiation therapy was administered to the spine tumor bed.
  
  
  CONCLUSIONS
  Yolk sac tumors, although rare, should be considered in the long list differential diagnosis of an otherwise healthy male presenting with conus medullaris or spinal cord compression from metastatic disease without evidence of a testicular mass. Prompt diagnosis with urgent decompression of neural structures and stabilization of the spine may result in improvement in neurological function.
authors.affiliation: UCLA Medical Center, Department of Orthopaedic Surgery, Los Angeles, CA.
authors.forename: Remi M
authors.initials: RM
authors.lastname: Ajiboye
authors.affiliation: UCLA Medical Center, Department of Orthopaedic Surgery, Los Angeles, CA.
authors.forename: Scott D
authors.initials: SD
authors.lastname: Nelson
authors.affiliation: UCLA Medical Center, Department of Orthopaedic Surgery, Los Angeles, CA.
authors.forename: Arya N
authors.initials: AN
authors.lastname: Shamie
keywords: Conus medullaris syndrome; Cord compression; Germ cell tumor; Pathologic fractures; Yolk sac tumor