MR imaging features of mitochondrial encephalomyopathies, lactic acidosis, and stroke-like episodes, Kearns-Sayre/Pearson syndrome have been described in the literature. We describe extensive white matter changes with abnormal signal intensity lesions involving the deep gray nuclei and myelinated white matter tracts in an 18-year-old female with a large-scale 7.4 kb mitochondrial DNA deletion and a atypical presentation of Kearns-Sayre syndrome. Restricted diffusion due to status spongiosus at the involved sites is also discussed.