Mazabraud's syndrome is the association of fibrous bone dysplasia and myxomas in soft tissues. We present a new case of this condition in a 52-year-old female patient who presented with pain in the epigastric region. As an incidental finding an abdominal CT showed multiple hypodense intramuscular masses in the upper third of her left thigh associated with a bone lesion in the left femur and left ischiopubic ramus. A plain X-ray showed bone damage in those two bones with a ground-glass pattern and gross trabeculation, consistent with fibrous bone dysplasia. The MRI showed multiple intramuscular masses hypointense in T1-weighted images and hyperintense in T2-weighted images with contrast peripheral enhancement after administering an intravenous contrast agent, with the exception of one of the masses, which showed central enhancement, suggesting multiple myxomas. Very few conditions exist that present as multiple intramuscular masses. The association of multiple intramuscular myxomas and fibrous bone dysplasia should raise suspicion of the presence of this syndrome, and allows for the follow-up of lesions, preventing unnecessary biopsies. The objective of this report is to describe a new case.