Isolated intracranial Whipple's disease--report of a rare case and review of the literature.

INTRODUCTION: Whipple's disease (WD) is a rare multisystemic infectious disease that can involve a variety of organs namely the gastrointestinal tract, lymphatic system, heart and nervous system. Myorhythmia is a hallmark of WD. Isolated CNS involvement is very rare.

CASE: We present a 50 year-old African-American woman with rapid cognitive decline, visual hallucinations, insomnia, dysarthria, and gait unsteadiness. She subsequently developed pendular nystagmus and gaze paresis. Serial brain MRI scans showed T2 hyperintense lesions in the left striatum and right parahippocampal gyrus. FDG-PET scan showed marked increase of glucose uptake in the left putamen. Serum and CSF PCR for Tropheryma whipplei was negative. Stereotactic biopsy of the lesion and tissue PCR was consistent with WD.

REVIEW OF LITERATURE: A systematic review identified 24 cases of isolated intracranial presentation of WD since 1975. Cases with systemic and extracranial manifestations were excluded.

DISCUSSION: In patients with rapidly progressive cognitive decline with negative workup for common etiologies, there should be a high index of suspicion for WD. Diagnosis of WD remains a challenge as traditional methods commonly fail to culture T. whipplei. PET scans can help in identifying areas of inflammation that can be biopsied. Our case proves that a negative serum and CSF PCR should not exclude CNS WD and a brain biopsy of the lesion with PCR assay should be performed when possible.