[Polyostotic fibro-osseus lesions associated with intramuscular soft tissue neoplasms].

A 40-year-old female patient presented with progressive painful soft tissue lesions in the left upper arm. Conventional radiography showed multicystic bone tumors of the left humerus, radius and ulna. The computed tomography (CT) scan showed no paraosteal spread. Magnetic resonance imaging (MRI) detected intramuscular tumors in the deltoid muscle, biceps humeri muscle and triceps humeri muscle which were T2-weighted hyperintense and T1-weighted hypointense. Postcontrast images showed a marginal enhancement. The findings corresponded to the rare Mazabraud's syndrome in which polyostotic fibrous dysplasia is associated with intramuscular myxomas.