1. A case of fibrous dysplasia in a woman aged fifty, with unilateral skeletal lesions, cutaneous pigmentation and possibly accelerated skeletal growth, is described.

2. At necropsy, the bony changes were found to be complicated by many of the changes of lipoid granulomatosis. Disseminated plaques of demyelinisation were found in the central nervous system.

3. The implications of the case are discussed.