Endocrine Abstracts

Morvan’s syndrome is a rare autoimmune disease characterised by peripheral nerve hyper excitability, CNS symptoms and autonomic dysfunction which can mimic other endocrine presentations with symptoms including hyperhidrosis, weight loss, neuromyotonia and insomnia. Morvan’s is associated with malignancy, in particular thymomas, suggesting paraneoplastic aetiology. This case is the first to associate Morvan’s with renal carcinoma and proposes insulin like growth factor 1 (IgF1) as a marker of disease activity.

A 52 year old man presented with non-specific symptoms including weight loss, hyperhidrosis and paraesthesia. He was extensively investigated and a CT scan revealed an incidental 5.4×5.1 cm left renal mass which was confirmed to be renal cell carcinoma following a curative nephrectomy. His symptoms persisted three months following surgery and a phaeochromocytoma, carcinoid tumour, thyrotoxicosis and Cushing’s syndrome were excluded. Furthermore, he had a normal positron emission tomographic scan that ruled out metastatic spread or a secondary malignancy. Interestingly, his IgF1 was found to be elevated at 103 nmol/l (normal range 8–39 nmol/l) which was confirmed on subsequent testing (although he had a normal oral glucose tolerance test excluding acromegaly). Voltage gated potassium antibodies (diagnostic of Morvan’s) were positive at 843 pM (normal <100 pM) confirming Morvan’s syndrome. He received an immunoglobulin infusion and high dose prednisolone and his symptoms improved significantly with a stepwise improvement in his IgF1 to 91 nmol/l then presently 42 nmol/l.

This case report is significant because it is the first case of Morvan’s syndrome with renal cell carcinoma and not a thymoma and proposes IgF1 as a marker of disease as the patient’s levels progressively improved with treatment and resolution of symptoms. Furthermore, voltage gated potassium channel antibodies should be considered in unexplained autonomic symptoms associated with malignancy and further research into the association of raised IgF1 with Morvan’s disease activity is indicated.