Chronic inflammatory polyneuropathy revealing malignant melanoma

Chronic inflammatory demyelinating polyneuropathy and malignancy: A systematic review

A systematic review of the literature was performed on the association of chronic inflammatory demyelinating polyneuropathy (CIDP) with malignancy. Hematological disorders are the most common association, particulalry non-Hodgkin lymphoma. CIDP frequently precedes the malignancy diagnosis, and there is a favorable CIDP response to treatment more than 70% of the time. Melanoma is the second most common association and may be accompanied by antiganglioside antibodies; CIDP shows a good response to immunotherapy. Other cancers are rare, with variable timings and presentations but good responses to immunomodulation and/or cancer therapy. Unusual neurological features such as ataxia, distal/upper limb predominance, or cranial/respiratory/autonomic involvement may suggest associated malignancy as may abdominal pain, diarrhea/constipation, poor appetite/weight loss, dermatological lesions, and lymphadenopathy. In the appropriate clinical and electrophysiological setting, CIDP associated with cancer should be considered. Immunomodulatory therapy, cancer treatment alone, or a combination may be effective. Muscle Nerve 57: 875-883, 2018.

Limbic encephalitis following immunotherapy against metastatic malignant melanoma

Novel immunotherapies are increasingly being used to treat malignant melanoma. The use of such agents has been associated with triggering autoimmunity. However, there has been a paucity in reports of limbic encephalitis associated with these immunotherapies. Pembrolizumab, a monoclonal antibody against programmed cell death antigen (PD-1), is currently being trialled in the UK to treat malignant melanoma. We report a unique case of antibody-negative limbic encephalitis presenting 1 year after starting pembrolizumab, in the context of malignant melanoma. The patient presented with progressive cognitive decline. MRI of the brain revealed signal change within the limbic structures. Cerebrospinal fluid studies confirmed evidence of inflammation with raised white cell count and protein. We were able to prevent further progression of symptoms by stopping pembrolizumab and treating the patient instead with steroids. We advocate considering autoimmune neuroinflammation as a differential for neurological disorders presenting in patients receiving PD-1 antagonist treatment and immunotherapy in general.

Chronic inflammatory demyelinating polyneuropathy associated with metastatic malignant melanoma of unknown primary origin

Paraneoplastic neurological syndromes (PNS) are rare manifestations of malignant disease. It is currently believed that most, if not all, PNS are autoimmune in nature. Proteins expressed on the surface of tumor cells trigger an immune response that cross-reacts with similar proteins in the nervous system, resulting in damage. Moreover, recent studies propose that the appearance of autoimmune phenomena in patients with malignant melanoma implies a strong antitumoral activity and constitutes a marker of improvement in overall survival. We describe a most unusual case of chronic inflammatory demyelinating polyneuropathy (CIDP) occurring in a patient with metastatic malignant melanoma of unknown primary origin who received treatment with interferon alpha-2b. We also review the relevant literature about this infrequent association, discuss on its pathogenesis and underline its importance as surrogate marker, useful to verify the antineoplastic treatment efficacy.