PET-positive polyostotic fibrous dysplasia mimicking Ollier disease

Fibrous dysplasia can be monostotic or, less commonly, polyostotic. The imaging features of polyostotic fibrous dysplasia may closely mimic those of metastatic bone disease, Paget disease, or enchondromatosis (Ollier disease). We present a unique case of polyostotic fibrous dysplasia in a 57-year-old female with a medical history of enchondromas involving the proximal phalanges of the left hand. The skeletal radiographs showed unilateral multiple bone lesions suggestive of polyostotic fibrous dysplasia. On magnetic resonance imaging, the lesions exhibited low-to-intermediate signal intensity on T1-weighted images and heterogeneous high signal intensity on T2-weighted images. Contrast-enhanced fat-suppressed T1-weighted images demonstrated moderate heterogenous enhancement. Integrated positron-emission tomography (PET)/computed tomography scan demonstrated increased (18)F-fluorodeoxyglucose (FDG) uptake within several bones, including the humerus, ilium, femur, and fibula, all on the left side. The maximal standardized uptake value of these lesions ranged from 2.18 to 3.78. We performed an open biopsy of the left humerus and histological examination confirmed the diagnosis of fibrous dysplasia. To the best of our knowledge, this is the first case of biopsy-proven FDG PET-positive polyostotic fibrous dysplasia with enchondromas of the hand.