Xanthogranuloma of the choroid plexus in the fat‐tailed dwarf lemur (Cheirogaleus medius)

Abstract

This report documents the death of two fat‐tailed dwarf lemurs (Cheirogaleus medius) maintained over 6 years each in our laboratory. Postmortem studies revealed xanthogranuloma of the choroid plexus, a mass replete with stored lipids, including cholesterol crystals. Six months prior to their deaths, both animals developed a peculiar head tilt and signs suggestive of neurological dysfunction. At autopsy, each had masses projecting into the lateral and IVth ventricles and an associated obstructive hydrocephalus. Cryostat sections of the brains of both lemurs showed histological features consistent with xanthogranuloma of the choroid plexus, a histologically benign and usually asymptomatic lesion found in up to 7% of human autopsies. This case is of special interest because of the unique feeding strategies in the fat‐tailed dwarf lemur. Since C. medius remains in torpor for 6 months out of the year during the time of food scarcity in the forests of Madagascar, the animal must accumulate large reserves of fat during its active period. In the laboratory, however, dwarf lemurs do not normally go into torpor, and the accumulated fat is not used. The finding of this tumor, therefore, suggests that the combination of a captive high‐fat diet and the unusual fat‐storage mechanisms utilized by C. medius contributed to the buildup of lipids and might be etiologically related to the development of those lesions.