Clinical and imaging features of newly recognized Kelch-like protein 11 paraneoplastic syndrome

A 32-year-old man presented with hearing loss and gait difficulties. His symptoms, including double vision, dysarthria, dysphagia, neck posturing, and tremors, evolved rapidly over 9 months. Within 15 months of onset, he used a wheelchair. He experienced no improvement after trials of intravenous methylprednisolone, intravenous immunoglobulins, plasmapheresis, and rituximab. His CSF testing was unrevealing except for elevated proteins and oligoclonal bands. He underwent serial brain imaging (figure). Extensive laboratory investigations, including nutritional, metabolic, mitochondrial, infectious, autoimmune, and paraneoplastic panels, were unremarkable (video). Expanded tissue-based immunofluorescence testing revealed positive Kelch-like protein 11 immunoglobulin G in the serum, a newly recognized paraneoplastic encephalitis.(1,2)