Primary Spinal Epidural Extraosseous Ewing's Sarcoma with Brachial Plexus Infiltration.

The Ewing's sarcoma family of tumors are aggressive malignant small round blue cell tumors of undifferentiated mesenchymal origin. Skeletal Ewing's sarcoma is a common entity that classically involves the diaphysis of the long bones, pelvis, ribs, and sacrum. Extraosseous Ewing's sarcoma (EES) is rare, most commonly presenting as a paravertebral mass lesion. Its manifestation as an anterior epidural mass lesion with extension along brachial plexus is an even rarer phenomenon. A 25-year-old male presented with neck stiffness and progressive weakness of the bilateral upper and lower limbs. Magnetic resonance imaging of the cervical spine revealed an anterior epidural mass lesion compressing the cervical cord and extending along the right brachial plexus, suggesting imaging differentials of EES and lymphoma. The patient underwent laminectomy with gross tumor resection, and histopathology confirmed a diagnosis of EES. EES should be kept in the differential diagnosis of anterior epidural mass lesions in young adults, specifically when the lesion shows extension along multiple neural foramina and nerve plexus.