NERVE SHEATH TUMORS-MRI

Schwannomas and neurofibromas are common variants of nerve sheath tumors. Pathologically Schwannomas are lobulated, well-circumscribed round or oval tumours that may show cystic changes, necrosis more often while neurofibromas are unencapsulated, fusiform, less well circumscribed and rarely show necrosis and cystic degeneration. They are most common intradural extramedullary spinal neoplasm, though extradural and dumb-bell masses too share 15% each..

Symptoms are same as of disc herniation i.e pain and radiculopathy. On plain films, widening of neural foramen may be seen along with anterior erosions with paraspinous soft tissue masses with posterior vertebral scalloping.

On MRI, they are mostly iso-intense on T1-weighted images, hyperintense on T2-weighted and enhance on contrast enhanced T1-weighted images.

Differential diagnosis includes : Meningiomas and ependymomas (at conus and filum terminale)

Our patient shows a TYPICAL dumb-bell shaped, lobulated schwannoma with intradural as well as extradural extension. It measures 54X23X52 mm and is iso-intense on T1 and heterogeneously hyperintense on T2 weighted images. Posterior scalloping of D12 vertebrae is well demonstrated in this case.

Submitted by Dr Sangeeta Aneja, MD Head of Dept, LLRM Meerut