Methods
A 79-year-old male presented with a rapidly enlarging mass over the radial aspect of his elbow. He was known to have metastatic HCC and was experiencing symptoms of pain over the posterior aspect of his right forearm and dorsal right hand.
On examination, he had pain on elbow flexion and supination of the affected limb. The mass was non-pulsatile, mobile without involving the overlying skin. Radial nerve assessment revealed normal power with reduced sensation in the radial nerve distribution. Activation of pronator teres and brachioradialis precipitated transient, severe exacerbation of pain. Median and ulnar nerve examinations were unremarkable.
Findings
Magnetic resonance imaging (MRI) showed a 13mm x 17mm x 15mm ovoid mass at the level of the radial head arising from the radial nerve. This was deep to the brachioradialis muscle and superficial to the margin of the brachialis muscle.
Surgical resection showed a metastatic deposit of hepatocellular carcinoma encircling small nerve fibres.
Discussion
The spread of HCC to the central nervous system (CNS) occurs in 1% of HCC patients (1). CNS lesions causing paralysis, impaired sensation and other mass effects are well described. In contrast, peripheral nerve metastases from HCC are rare. Case reports of facial nerve palsy and paralysis from extrahepatic temporal bone HCC lesions have been described (2), as have orbital metastatic lesions causing proptosis and decreased vision (3). These lesions often affect the peripheral nerve because of compression, rather than direct metastatic invasion of the nerve, as seen in the above case.
Conclusions
This is a rare case of metastatic HCC to the radial nerve causing peripheral nerve compression. Metastatic compression or invasions of peripheral nerves should be considered as a differential diagnosis for patients who present peripheral nerve symptoms on the background of metastatic disease.