Polyostotic fibrous dysplasia: imaging findings of a controversial case

Fibrous dysplasia is a rare non-neoplastic tumor-like congenital bone disease that is most likely associated with GNAS gene mutations, with a broad spectrum of clinical presentations, ranging from isolated monostotic and polyostotic forms to other extra-skeletal associated manifestations as in McCuneAlbright syndrome. It is responsible for bones weakening and increased fragility, making it prone to fractures. A 65-year-old female patient was referred to our radiology department for cervical and dorsal pain, with a previous diagnosis of incidental cervical and dorsal bone lesions that are suspected for metastases. X-ray, computed tomography, and magnetic resonance imaging were performed with a precise diagnostic suspicion of fibrous dysplasia that is confirmed by bone biopsy. Fibrous dysplasia principally affects the bone and is characterized by bone replacement itself by dysplastic fibrous tissue. According to the number of affected bones and their association to endocrine alterations, it is classified into three categories monostotic, polyostotic, and Albrights disease. Differential diagnosis with multiple myeloma among others and the best treatment decision was made.