Les syndromes neurologiques paranéoplasiques

[Auto-immune diseases and cancers. Second part: auto-immune diseases complicating cancers and their treatment]

Autoimmune diseases may reveal or occur during the course of a neoplasia or its treatment. Autoimmune cytopenia, especially haemolytic anaemia, is common in lymphoproliferative disorders such as chronic lymphoid leukemia. The link between cancer and myositis is well established. Dermatomyositis is associated with an increased relative risk of cancer of 3.4 to 4.4. A combination of detection of antibodies against p155 and TEP-computed tomography may be the best approach to ascertain the presence of occult malignancy in patients with dermatomyositis. A cutaneous or a systemic vascularitis may reveal a cancer, most often a haematological malignancy such as hairy cell leukemia. Paraneoplastic polyarthritis have been described in particular with adenocardinoma of the lungs. Underlying neoplasia should be considered in male smokers patients with new onset polyarthritis and poor health status. The prevalence of autoimmune conditions in myelodysplastic syndromes is 10 to 30%. Vasculitis and relapsing polychondritis are the most commonly reported manifestations. Immune manifestations can also be related to treatment. The most common treatment complications are autoimmune haemolytic anaemia with fludarabine and thyroiditis related to interferon and cervical radiotherapy.

[Sudden death occurring after anti-Hu associated paraneoplastic cerebellar degeneration and dysautonomia revealing a small cell lung carcinoma]

INTRODUCTION

Paraneoplastic syndromes are a rare cancer complication with a frequent subacute evolution.

OBSERVATION

A 62-year-old man was admitted presenting with a cerebellar syndrome and orthostatic hypotension with dysautonomia. Anti-Hu antibody research was positive. A subcarinal adenopathy biopsy found out a small cell lung carcinoma. Despite a treatment with immunoglobulin and chemotherapy, the patient died suddenly, after a raise of dysautonomia symptoms.

CONCLUSION

Sudden death observations represent exceptional complications of paraneoplastic syndrome. They might be secondary to arrhythmias, ictal asystol or laryngospasm. Systematic research of paroxystic heart arrhythmias with holter-ECG in paraneoplastic syndrome may prevent sudden deaths.

Paraneoplastic disorders of the central and peripheral nervous systems

Paraneoplatic neurologic syndromes (PNS) have been seminally defined as acute or subacute neurological syndromes resulting from nervous system dysfunction that is remote from the site of a malignant neoplasm or its metastases. However, in respect to our current understanding of their pathogenesis we may redefine these disorders as cancer-related dysimmune neurologic syndromes. We first deal with the epidemiology and the pathogenesis of PNS, then the different classic PNS are reviewed with clinical features according to the associated onconeuronal antibodies. Finally, therapeutic approaches are discussed.

[Favourable outcome after treatment with rituximab in a case of seronegative non-paraneoplastic Lambert-Eaton myasthenic syndrome]

INTRODUCTION

Lambert-Eaton myasthenic syndrome is a rare and autoimmune presynaptic disorder of the neuromuscular junction, due in 85% of cases to autoantibodies directed against voltage-gated calcium channels. It is a paraneoplastic disorder in 50 to 60% of cases. Diagnosis involves a proximal muscle weakness and areflexia, associated with a significant increment after post-exercise stimulation in electrophysiological study. Symptomatic treatment is based on 3,4-diaminopyridine. No etiological treatment has proven its efficacy in both paraneoplastic and non-paraneoplastic Lambert-Eaton myasthenic syndrome.

CASE REPORT

We report a 41-year-old man who presented with a seronegative non-paraneoplastic Lambert-Eaton myasthenic syndrome in whom conventional immunosuppressive treatments (corticosteroids, azathioprine) failed, and who eventually improved after treatment with rituximab.

CONCLUSION

Rituximab was an effective and well-tolerated treatment in this case of seronegative non-paraneoplastic Lambert-Eaton myasthenic syndrome. Its indication should be discussed when conventional immunosuppressive therapy fails in both seropositive and seronegative patients.

[N-methyl-d-aspartate receptor antibody encephalitis: a treatable disorder involving B-lymphocytes. A report of two patients]

INTRODUCTION

N-methyl-D-aspartate receptor antibody (anti-NMDA-r AB) encephalitis has been recently identified. We report two cases illustrating the clinical features, response to immunomodulatory treatment and involvement of B-lymphocytes that characterizes this disorder.

CASE REPORTS

These patients illustrated the classic clinical features of anti-NMDA-r AB encephalitis including occurrence in young female, presence of severe neurological and psychiatric manifestations with confusion, seizures, mutism, hypovigilence and involuntary movements, and inflammatory cerebrospinal fluid. Both patients improved after immunotherapy. In case 1, the encephalitis was associated with an ovarian teratoma containing neuronal elements. In case 2, there was no tumor identified. A brain biopsy showed prominent perivascular B-cells infiltrates with some T-cells distributed in the brain parenchyma.

CONCLUSION

Anti-NMDA-r AB encephalitis is certainly not rare and needs to be promptly recognized and treated. An associated neoplasia is inconstant and the pathophysiology involves humoral immunity.