[Brainstem variant of reversible posterior leukoencephalopathy syndrome with a prolonged clinical course: a case report].

A 38-year-old man gradually developed gait instability, dysarthria, and dysphagia over two months associated with an elevated blood pressure after starting hemodialysis therapy for diabetic nephropathy. Brain MRI studies indicated vasogenic edema in the brainstem, extending from the lower midbrain to the upper medulla oblongata. The patient's high blood pressure was refractory to treatment, and his neurological disabilities and MRI abnormalities progressed. FDG-PET, MR spectroscopy, and cerebrospinal fluid studies did not suggest neoplastic pathologies. The patient was diagnosed with a brainstem variant of reversible posterior leukoencephalopathy syndrome, and received three courses of steroid pulse therapy. After the pulse therapy, the clinical manifestations and MR findings improved. By maintaining strict management of blood pressure and body water balance during hemodialysis, he did not experience any further clinical exacerbation, and the lesion on MR images continued to regress. Ten months after the pulse therapy, T1-weighted images showed slightly hyperintense signal. This case suggests that reversible posterior leukoencephalopathy syndrome (RPLS) may take a chronic clinical course without acute onset.