Extramedullary intradural spinal tumors: a pictorial review

Defining the location of tumors and mass lesions of the spine in relation to the spinal cord and the dura is of the utmost importance as certain types of lesions tend to occur in certain locations. The differential diagnostic considerations will vary according to location of the mass lesion as will the treatment and prognosis of these various lesions. The category of extramedullary intradural masses includes a variety of lesions from meningiomas and nerve sheath tumors (neurofibromas, schwannomas) to less common tumors (hemangiopericytoma), metastases, benign tumors (lipoma, dermoid, epidermoid), inflammatory disorders (arachnoid adhesions, sarcoidosis), vascular lesions (spinal-dural arteriovenous fistula), and cystic lesions (perineural or Tarlov cysts). Characteristic magnetic resonance imaging findings are helpful for localization and characterization of these lesions before treatment, as well as for follow-up after treatment. We present a pictorial review of the various extramedullary intradural lesions of the spine, with pathologic correlation. We discuss imaging features that are typical for the various entities and describe various therapeutic options that are important considerations for surgical treatment of these lesions.