Central pontine and extrapontine myelinolysis despite careful correction of hyponatremia: clinical and neuropathological findings of a case

We report clinical, radiological and pathological findings in a patient with central pontine and extrapontine myelinolysis. The patient was a 61-year-old woman who had a radical mastectomy for breast cancer. Based on clinical evidence, acute hyponatremia had set in only a few days before onset of symptoms. The patient’s disease progressed in two stages and became more severe during slow hyponatremia correction after 9 days from onset. Diffusion MRI provided early evidence of neurological lesions. In spite of a therapeutic attempt, the patient died unexpectedly 18 days after onset of her neurological disease due to massive pulmonary embolism. Histologically, our findings confirmed that the major features of central pontine myelinolysis in the acute stage are demyelination, the presence of large amounts of macrophages with no lymphocytic inflammatory reaction, and moderate astrocytosis. It is interesting to note that a monotypic immunological reaction persisted 19 days after radiological demonstration of parenchymal alterations.