Paraneoplastic sensory-motor neuropathies
The association of cancer and peripheral neuropathy is not unusual and
it has long been underlined that a careful follow up of patients with
peripheral neuropathy of unknown origin may eventually result in the
diagnosis of cancer providing an aetiology to the neuropathy. However,
such an association does not necessarily indicates that the neuropathy
is paraneoplastic as it may result from chance. The problem is particularly
crucial with sensory-motor neuropathies and cancer for which less than
30% of patients have onconeural antibodies (ab). The following commentary
does not take into account the specific problem of neuropathy and malignant
monoclonal gammopathies.
Definite sensory-motor peripheral neuropathies
These neuropathies occur with anti-Hu
or anti-CV2 ab, some patients having
both. With anti-Hu ab, subacute sensory neuronopathy (SSN) is responsible
for the sensory manifestations and motor symptoms usually result from
motor neurone degeneration. About 15%-30% of patients with anti-Hu ab
and peripheral neuropathy present with a sensory and motor neuropathy,
one third having an equal proportion of sensory and motor involvement.
As the distribution of symptoms is frequently asymmetrical or multifocal,
the disorder can be misdiagnosed as mononeuritis multiplex or polyradiculopathy.
An acute and severe evolution in the four limbs may mimic a Guillain-Barré
syndrome. There is indications that in patients with SSN, inflammatory
lesions may extend into the peripheral nerves. Vasculitis or demyelinating
lesions have both been reported on nerve biopsy. The pathophysiology
of these nerve changes is unclear as the Hu proteins are not normally
expressed in the peripheral nerve.
Peripheral neuropathy occurs in 60% of patients with anti-CV2
ab. In two third of cases it is a sensory-motor neuropathy affecting
preferentially the lower limbs. Pain is less frequent than with anti-Hu
ab. Electrophysiological and pathological studies indicate an axonal
or axonal and demyelinating process. Patients with both anti-Hu and
anti-CV2 ab may combine SSN and nerve lesion. About 65% of patients
simultaneously have central nervous system disorder, autonomic neuropathy
or eye involvement.
Possible paraneoplastic peripheral neuropathies
Different forms of neuropathy fall in this group. Contrary to the neuropathies
associated with onconeural antibodies, the disorders are usually restricted
to the peripheral nervous system and the associated tumours are varied.
The neuropathies include Guillain-Barré syndrome, chronic or
relapsing sensory-motor neuropathies some of which fulfilling the diagnostic
criteria of chronic inflammatory demyelinating polyneuropathy, neuropathies
with vasculitis, chronic axonal neuropathies, and brachial plexopathy.
There is indication that neuropathies occurring within a short delay
with cancer are frequently of an inflammatory type. However, whether
the tumour is responsible for the disorder is still unknown. Rare cases
of patients with melanoma, peripheral neuropathy, and antibodies reacting
with gangliosides common to both the tumour and the peripheral nerve
suggest that a crossed immunological process may occur in some neuropathies.
Paraneoplastic neuropathies and vasculitis.
The clinical presentation is mononeuritis multiplex or symmetrical
sensorimotor axonal neuropathy. High ESR and high CSF protein concentration
are frequent laboratory findings. Extra-neurological manifestations
are absent. Some patients improve with the treatment of the tumour and
others with immunosuppressants. In fact, paraneoplastic vasculitic neuropathies
correspond to at least two different nosological situations.
-
1- In a first group of patient, vasculitis is
a satellite of subacute sensory neuropathy either confirmed by autopsy
or highly probable on clinical and electrophysiological data. These
patients have small cell lung cancer and, when tested, anti-Hu
ab are detected. In one case, vasculitis was also present in
muscle biopsy.
-
2- In a second group of patients, peripheral
neuropathy is the only clinical manifestation. The cancers in this
group of patients are various including lymphoma, Hodgkin’s
disease, uterus, stomach and non small cell lung cancer. The frequency
of cancer in patients with nerve vasculitis has been estimated from
5.5% to 14% which appears to be higher than in the general population.
Controlled epidemiological studies are needed to confirm these results.
Selected references
1. Rudnicki SA, Dalmau J. Paraneoplastic syndromes of the spinal cord,
nerve, and muscle.. Muscle Nerve. 2000;23:1800-18.
2. Smitt PS, Posner JB. Paraneoplastic peripheral neuropathy. In Latov
N, Wokke JH, Kelly JJ, eds. Immunological and infectious diseases of
the peripheral nerves. Cambridge: Cambridge University Press, 1998:208-24.
3. Antoine JC, Mosnier JF, Absi L, et al. Carcinoma associated paraneoplastic
peripheral neuropathies in patients with and without anti-onconeural
antibodies. J Neurol Neurosurg Psychiatry 1999; 67:7-14.
4. Antoine JC, Honnorat J, Camdessanche JP, et al. Paraneoplastic anti-CV2
antibodies react with peripheral nerve and are associated with a mixed
axonal and demyelinating peripheral neuropathy. Ann Neurol 2001; 49:
214-21.
5. Kloos L, Sillevis Smitt P, Ang C W, et al. Paraneoplastic ophthalmoplegia
and subacute motoraxonal neuropathy associated with anti-GQ1b antibodies
in a patient with malignant melanoma. J Neurol Neurosurg Psychiatry
2003; 74:507–9
6. Younger DS, Dalmau J, Inghirami G, ET AL. Anti-Hu-associated peripheral
nerve and muscle microvasculitis. Neurology 1994 ; 44: 181-3.
7. Vincent D, Dubas F, Haw JJ, et al. Nerve and muscle microvasculitis.
J Neurol Neurosurg Psychiatry 1986; 49:1007-10.
8. Oh SJ. Paraneoplastic vasculitis of the peripheral nervous system.
Vasculitis and the nervous system, Neurologic Clinics Vol 15, number
1997 ; 4: 849-63.
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