The clinical and computerized tomodensitometric data and postmortem examination findings from a case of xanthogranuloma of the third ventricle, producing hydrocephalus, are described. A review of 8 recently reported cases resembling ours shows that, on clinical and radiological grounds, third ventricle xanthogranulomas are usually indistinguishable from colloid cysts. From an embryologic and pathologic point of view, these entities seem also to be closely related.