High-signal periventricular lesions in patients with sarcoidosis: neurosarcoidosis or multiple sclerosis?

The vast majority of periventricular abnormalities visualized with MR imaging in patients less than 50 years old represents multiple sclerosis (MS) lesions. There are many other causes of periventricular lesions, most of which can be differentiated from MS on the basis of history and physical or MR findings. Five cases of biopsy- or Kveim test-proved sarcoidosis with MR findings consistent with MS are reported. Each of these patients, diagnosed as having sarcoidosis, had symptoms identical to those seen in MS. Although these patients have not had histologic characterization of the intraparenchymal lesions seen on MR, they illustrate the difficulty of differentiating sarcoidosis with CNS involvement from MS in some patients on the basis of clinical, radiographic, electrodiagnostic, or CSF testing. This series contributes to a growing body of evidence that neurosarcoidosis probably should be included in the differential diagnosis of isolated periventricular lesions in patients less than 50 years old.