Paraneoplastic neurological syndromes: unusual presentations of cancer. A practical review.

INTRODUCTION

Paraneoplastic neurological syndromes (PNS) are uncommon and imperfectly understood and, therefore, are frequently underdiagnosed.

METHODS

We review the current literature on the clinical presentation, diagnosis, pathophysiology and treatment of PNS.

RESULTS

PNS are a heterogeneous group of neurologic disorders caused by an immune response to an underlying malignancy. A 3-step diagnostic process is necessary to establish the diagnosis. We review the role of onconeural antibodies in the diagnosis and pathogenesis of PNS and describe recent advances in treatment, focusing on paraneoplastic encephalomyelitis, limbic encephalitis, paraneoplastic cerebellar degeneration, opsoclonus-myoclonus syndrome, subacute sensory neuronopathy and Lambert-Eaton myasthenic syndrome

CONCLUSION

PNS often antedate the diagnosis of cancer, offering an opportunity for detecting cancer at an earlier and curable stage. Tests for paraneoplastic antibodies are often negative and do not rule out the diagnosis of a paraneoplastic syndrome. Certain clinical presentations should suggest a paraneoplastic syndrome, even in the absence of paraneoplastic antibodies, and prompt a thorough search for occult malignancy.