Brachial Plexus Tumour

brachial plexus tumour

This 47 year-old male patient presented with right C5-C6 weakness and a lump in the right supraclavicular fossa. Selected sequences from an MRI study (click image for arrows) show a rounded well-defined homogeneously enhancing lesion centred on the superior trunks of the brachial plexus, immediately lateral to the scalenus muscles. This lesion is of high signal on water-weighted sequences. The findings are in keeping with a nerve sheath tumour, either neurofibroma or schwannoma.

The brachial plexus lies in the prevertebral space, between scalenus medius and scalenus anterior. Both schwannoma and neurofibroma are well-circumscribed benign tumours. The distinction frequently cannot be made with imaging alone. Both types of tumour may scallop adjacent bone. Neurofibromas may show fatty degeneration, and may be close to water density on CT. Schwannomas may be heterogeneous when large, with cyst formation, haemorrhage or calcification.

References:
1. Dahnert W. Radiology Review Manual. 5th edition. Lippincott, Williams & Wilkins 2003
2. Harnsberger HR. Handbook of Head and Neck Imaging 2nd edition. Mosby 1995.

Credit: Dr Laughlin Dawes