Symptomatic xanthogranuloma of the choroid plexus of the third ventricle. A new case with ultrastructural study.

The clinicopathological findings in a new case of a surgically removed, symptomatic xanthogranuloma of the third ventricle are reported. Ultrastructural study showed that the lining epithelium of the tumor was composed of typical leptomeningeal cells, and that transitional forms from leptomeningeal cells into xanthomatous cells were present in the underlying fibrous capsule. These findings support the hypothesis of a leptomeningeal origin of the foamy cells in the present case. The ten cases reported previously of symptomatic xanthogranuloma of the third ventricle are reviewed. We suggest that xanthogranulomas of the choroid plexus might represent a heterogenous entity arising from xanthomatous changes involving various types of cells.