IMAGE OF THE WEEK 2013

WEEK 19

SPINAL SCHWANNOMAS

Figure 1: MRI T1 sequence saggital section of the lumbar spine showing an isointense space occupying lesion at L5 level. (Click on image to enlarge)	Figure 2: MRI T2 sequence saggital section of the same lumbar spine showing a hyperintense space occupying lesion at L5 level. (Click on image to enlarge)	Figure 3: MRI saggital section of the same lumbar spine following gadolinium administration, showing an avidly enhancing space occupying lesion at L5 level. (Click on image to enlarge)

Spinal schwannomas are benign tumours arising from nerves in the spinal canal.

Schwannomas can arise from any nerves in the body, perhaps the best known being the vestibular (aka acoustic) schwannomas arising at the cerebellopontine angle in the

brain.

Tumours of the spinal canal are classified on their location with respect to the dura and the cord.  Spinal schwannomas fall into the intradural extramedullary category, being within the thecal sac, but outside of the cord.  They are the commonest tumour in this category.

These lesions are usually very well defined arising from dorsal nerve roots and present with pain or incidentally on imaging performed for an alternative indication.

MRI is the only sensitive imaging modality for the detection of schwannomas with the administration of contrast (gadolinium) greatly assisting in their identification, especially if small.

A schwannoma typically has the following appearances on MRI:

1. Isointense on T1 (therefore hard to see on this sequence)     (Figure 1)

2. Hyperintense on T2  (Figure 2)

3. Avidly enhancing following gadolinium administration   (Figures 3 and 4)

Schwannomas and neurofibromas may be almost identical in appearance, however schwannomas often have small amounts of cystic of haemorrhagic change within, clinching the diagnosis.

Surgery is indicated if symptoms are problematic, as these tumours are almost universally histopathologically benign.

Images and text contributed by

Dr Ian Bickle, Department of Radiology,RIPAS Hospital

All images are copyrighted and property of RIPAS Hospital.