A patient with worsening mobility: a diagnostic challenge.

Worsening mobility and "off legs" are common reasons to seek a medical opinion. A 62-year-old gentleman, previously fit and healthy, was referred to a district general hospital in the UK with worsening mobility. The initial clinical features were suggestive of Miller Fisher syndrome (MFS). Initial investigations were unremarkable apart from mild hypokalemia. Despite correction of the hypokalemia and immunoglobulin infusion, the patient's condition deteriorated. The presence of hypokalemia raised the possibility of underlying malignancy with ectopic ACTH secretion. A CT of the chest/abdomen showed a mediastinal mass. A post-mortem examination revealed a metastatic anaplastic pancreatic carcinoma. To the best of our knowledge, this is the first report in which MFS has occurred in association with pancreatic carcinoma. This case highlights that malignancy should be considered as a possibility in patients presenting with MFS and/or worsening mobility.