IntroductionFibrous dysplasia (FD) is a non-heritable genetic disorder in which normal bone is replaced by immature, irregularly distributed fibro-osseous tissue. This condition can lead to deformities, fractures, pain, and functional impairments.[1] Fibrous dysplasia (FD) is caused by a sporadic mutation in the α-subunit of the Gs stimulatory protein, resulting in bone being replaced and distorted by poorly organized, structurally weak fibrous tissue.[2] FD accounts for 5% to 7% of all benign bone tumors. It is classified as monostotic when only one bone is affected and polyostotic when multiple bones are involved. The maxilla or zygomaticomaxillary complex is the most commonly affected craniofacial bone, followed by the mandible, frontal, sphenoidal, ethmoidal, parietal, temporal, and occipital bones..Since mild, asymptomatic fibrous dysplasia (FD) is often discovered incidentally during imaging studies, many patients may remain undiagnosed. Additionally, FD lesions are poorly characterized, which raises the possibility that monostotic FD is overdiagnosed in cases of solitary bone lesions. Not all patients diagnosed with monostotic FD undergo comprehensive whole-body and endocrine evaluations, making it difficult to determine the true prevalence of polyostotic FD and its various subtypes.[3, 4]FD can present at any age, but it most commonly occurs before the age of 15, typically around 10 years old. In the craniofacial region, FD tends to develop particularly early, with most lesions being established by the age of 3.[5]Central giant cell granuloma (CGCG) primarily affects younger individuals, with a higher prevalence in females. It is more commonly found in the mandible and is more prevalent in the anterior region than in the posterior jaws. CGCG often crosses the midline and leads to asymptomatic expansion of the cortical plates, exhibiting variable radiographic appearances that can range from unilocular to multilocular radiolucencies.[6, 7] It is suggested that CGCG is more of a reparative lesion than a neoplastic one. Its clinical behavior can vary widely, ranging from an indolent, slow-growing, asymptomatic mass to an aggressive lesion that causes pain, root resorption, and a tendency to recur after excision.[8]Hybrid lesions are defined as those that exhibit distinct features from different pathologies within a single lesion. The literature has documented the co-occurrence of central giant cell granuloma (CGCG) with fibro-osseous lesions such as fibrous dysplasia (FD), cemento-osseous fibroma (COF), cemento-osseous dysplasia, and Paget’s disease.[9, 10]While the simultaneous occurrence of FD and CGCG has been reported in numerous cases, there are no documented instances of FD developing after the surgical removal of CGCG a decade later. In this paper, we present a case of FD in a 50-year-old female with a history of CGCG enucleation performed 10 years prior.