Spinal primitive neuroectodermal tumor mimicking as chronic inflammatory demyelination polyneuropathy: a case report and review of literature.

We report a young boy who presented with progressive weakness of lower extremities associated with areflexia and abnormal electrophysiological findings initially suggestive of chronic inflammatory demyelinating polyneuropathy. Initial lumbosacral spinal magnetic resonance imaging (MRI) showed thickened descending spinal nerve roots only. Immunomodulating therapy was given but with limited clinical response. Repeated spine magnetic resonance imaging showed cauda equina and also new spinal cord extramedullary contrast enhancement. The initial extensive investigations including open biopsy did not point to any specific diagnosis. Only through pursuing a repeated biopsy, the diagnosis of the spinal peripheral primitive neuroectodermal tumor was confirmed. This case highlights the diagnostic challenges of the spinal peripheral primitive neuroectodermal tumor that could have an initial chronic inflammatory demyelinating polyneuropathy-like presentation. The literature review confirms that this is a rare condition and cauda equina origin has only been reported in adults and teenagers, and this is the first reported case in a young child.