Granulocytic sarcoma: a rare cause of sciatica.

We describe a case report of a man aged 56 years with a 4-month history of right-sided sciatica-type pain with subclinical disc prolapse evident on MRI. Worsening pain together with the appearance of a tender mass in his right buttock prompted further imaging, which demonstrated an infiltrative mass engulfing the lumbosacral plexus. This was later shown to be a granulocytic sarcoma on biopsy. Intervertebral disc herniation can be an incidental finding and is not always the cause of sciatica.