Posterior reversible encephalopathy syndrome

Case contributed by Anthony Nuñez
Diagnosis almost certain


Patient with a recent hematopoietic stem cell transplantation. On immunosuppressive therapy and corticosteroids in high doses. Presented with altered mental status, hypertension and seizures in the past hour.

Patient Data

Age: 15 years
Gender: Male

In the left upper parietal region, there is an area of decreased attenuation and loss of the grey-white matter junction in a nonvascular, watershed distribution.

Eight hours later


Multiple cortical and subcortical foci of signal abnormality (hypointense in T1 and hyperintense in T2) in frontal, parietal and temporal lobes. No infarctions. No hemorrhage. 

Case Discussion

Although its name is posterior reversible encephalopathy syndrome (PRES), there are three main imaging patterns:

  • holohemispheric at watershed zones pattern
  • superior frontal sulcus pattern
  • dominant parieto-occipital pattern

There are many differentials as posterior circulation stroke (restriction on DWI/ADC), infectious encephalitis, venous sinus thrombosis and basilar artery thrombosis among others. 

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