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Malignant melanoma is an immunological tumour, and the glycoproteins on the surface of melanoma cells share immunogenic similarity with cells in the central and peripheral nervous system. Several clinical signs have been suggested to result from this similarity including vitiligo, syndrome of inappropriate antidiuretic hormone secretion (SIADH), and chronic inflammatory demyelinating polyneuropathy.1,2
We describe a patient with metastatic melanoma in the eye, who developed uveitis associated with ascending motor neuropathy. Enucleation of her blind painful eye resulted in marked improvement in her neurological abnormalities.
A 21 year old woman with a history of stage III cutaneous melanoma presented with anterior uveitis in her left eye. Visual acuity, intraocular pressure, and posterior pole examinations were within normal limits. Right eye examination was unremarkable. A diagnostic anterior chamber tap, left eye, revealed melanoma tumour cells.
One month later she developed a profound ascending motor polyneuropathy compatible with the diagnosis of Guillain-Barré syndrome. Clinical examination showed weakness of her upper and lower extremities, and decreased reflexes with no signs of sensory neuropathy. Lumbar puncture demonstrated 3 white blood cells ×106/l. Magnetic resonance imaging of her thorax, cervical and lumbar spine showed no evidence of spinal cord or leptomeningeal disease.
The neurological symptoms worsened proportionally to the disease progression in her eye, and the level of neuron specific enolase (NSE) rose from a low value of 16 to a high value of 36 ng/ml. She was treated with several courses of high dose intravenous gamma globulin (IVIG) with slight but temporary improvement.
Six weeks after initial presentation, because of severe refractory disease in the left eye (fig 1), she underwent a left eye enucleation. Histopathological examination showed malignant melanoma involving the ciliary body, iris, trabecular meshwork, and vitreous cavity (fig 2). Since the enucleation her polyneuropathy has markedly improved. NSE decreased to 12 ng/ml (normal 0–10). She has continued to receive IVIG and autologus dendritic cell vaccine and, 18 weeks after enucleation, showed partial (>50%) resolution of the polyneuropathy with substantial but as yet incomplete recovery of lower and upper extremity weakness.
The patient presented with uveitis and metastatic melanoma in her left eye. She developed a severe ascending motor polyneuropathy compatible with the diagnosis of Guillain-Barré syndrome. Enucleation of the blind, painful left eye resulted in substantial clinical and laboratory improvement in the polyneuropathy.
Ascending motor polyneuropathy in our patient may have been caused by an immune reaction directed to antigens in the tumour that cross reacted in the nervous system. Marked improvement in her overall peripheral muscle strength after the enucleation suggests a relation between the progressive dysimmune polyneuropathy and the intraocular involvement. More evidence of a tumour related immune response was shown by post-enucleation decrease in the level of NSE, a specific marker for metastatic disease in melanoma where its increase points to disease progression.3
Various paraneoplastic neuropathies have been described in association with cancer, including subacute sensory neuropathy/paraneoplastic encephalomyelitis,4 Guillain-Barré syndrome, and axonal polyneuropathy;5 and specifically in melanoma: chronic inflammatory demyelinating polyneuropathy,1 ophthalmoplegia, and subacute motor axonal neuropathy.2
The relation between enucleation and improvement of the neuropathy is not clear; improvement may have been a spontaneous remission. However, the appearance of neuropathy soon after the onset of uveitis and the partial (>50%) resolution after enucleation raise the possibility that molecular mimicry and antigenic cross reaction were the cause of the polyneuropathy. Enucleation, by reducing the cross reacting antigens, is likely to have contributed to resolution of the polyneuropathy.