Hematoxylin/eosin stain shows epithelioid type cells with sightly vacuolated eosinophilic cytoplasm and large nuclei. One cell contains small rod like structures with indistinct borders (figure A). These cells present a strong cytoplasmic reactivity with the PAS stain (figure B). Grocoot stain reveals an intracytoplasmic positivity within the PAS positive cells (figure C). Immunohistochemistry to further characterized these cells showed the cells to be positive for CD68 (macrophage type cell marker), negative for cytokeratin, LCA, GFAP and CD1a. FITE stain for mycobacterium and Gram stain were negative. These findings are compatible with the histological diagnosis of cerebral Whipple’s disease.

In order to confirm the diagnosis, less than 300µl of intra-ventricular fluid removed during surgery and CSF were sent for molecular diagnosis. PCR using specific primers for T. Whippellii was negative. PCR using universal bacterial primers revealed the presence of a very faint band for 16SrRNA but sequencing was not possible. Immunohistochemistry for T. Whippellii was performed on the section and was negative (courtesy of Dr. Leipidi, Marseille, France). Electron microscopy performed on deparaffinized tissue was inconclusive. An intestinal biopsy was performed and showed no pathology. PCR was also negative.

Ref: Scandinavian Journal of infection Diseases, 1999, 31, 411-4.


  Fig. 4