Treatable Leukoencephalopathy in a Patient with Hypophosphatemia

We report the first patient with pathologically proven leukoencephalopathy associated with hypophosphatemia. A 61-year-old woman had repetitive episodes of decreased consciousness with pontine and pallidal lesions and extensive leukoencephalopathy on MRI, later found to be associated with hypophosphatemia. Although hypophosphatemia has been linked to central pontine and extrapontine myelinolysis (osmotic myelinolysis), lesions in the deep white matter have not been reported. Brain biopsy performed during the first diagnosis process revealed nonspecific demyelination with gliosis, a finding similar to that of chronic osmotic myelinolysis. After normalization of phosphate levels, her consciousness completely improved and MRI abnormalities partly resolved. We should consider that leukoencephalopathy can be associated with hypophosphatemia, which is often treatable.