Novel neuroimaging findings in a patient with cerebral Whipple's disease: a magnetic resonance imaging and positron emission tomography study.

The authors report a 43-year-old patient with histopathologically proven cerebral Whipple's disease. Magnetic resonance imaging (MRI) revealed a multilayered left frontal lesion without mass effect, no perifocal brain edema, no contrast enhancement, and a thin shell of fluid signal that presented as an incomplete, open ring. An [11C]methionine positron emission tomography (PET) study showed low uptake below the threshold that is characteristic for brain tumors. In precise co-registration to the MR images, the PET data showed that increased uptake was mainly located in the direct adjacent part of the MRI lesion. The fluid signal on MRI corresponded to the extensive outflow of fluid from the lesion, which was observed during neurosurgical resection, and also to the neuropathological findings. The authors conclude that this cerebral manifestation of Whipple's disease made a unique and hitherto undescribed appearance on MRI; uptake pattern of PET amino acid tracer may help in the preoperative distinction of inflammatory from neoplastic lesions.