Xanthogranuloma and xanthoma of the choroid plexus: evidence for different etiology and pathogenesis.

Xanthogranulomas of the choroid plexus (XGCP) and xanthomas of the choroid plexus (XCP) are generally held to be closely related to each other. Obtained by autopsy 17 cases with XGCP and 21 cases with XCP were investigated. Foamy cells were confirmed to be constitutional for both lesions. Immunohistochemically their antigen profile was shown to be of histiocytic type. A dense siderosis emerged as a consistent feature of XGCP but not of XCP. In no case both tumors were found associated. Analysis of clinical data revealed hyperlipidemia in 15 out of 17 cases with XCP but in only 3 out of 13 cases with XGCP (p < 0.01; in 4 cases of each sample pertinent data were pending). The male-to-female ratio was 14:3 in cases with XGCP and 13:8 in cases with XCP; when combined with data of other authors the male preponderance in XGCP became statistically significant. In conclusion, XGCP and XCP emerged as different independent lesions. XCP appeared to be closely related for example to tendon xanthomas of the skin which are well established as being diagnostic of hyperlipidemia. XGCP, on the other hand, are most likely to correspond to cholesterol granulomas of extracranial provenance. Thus, the data presented strongly recommend the replacement of the term "xanthogranuloma of choroid plexus" with the term "cholesterol granuloma of choroid plexus".