Fibrous Dysplasia Radiographic — ORE Part 1 MCQ

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ModerateOral PathologyFibrous Dysplasia RadiographicORE Part 1

A patient presents with a slowly enlarging, firm, painless swelling of the left mandibular ramus. OPG shows a ground-glass radiopacity blending imperceptibly with the surrounding bone. The lesion does not have a well-defined border. What is the most likely diagnosis?

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Correct answer: A — Fibrous dysplasia

Fibrous dysplasia (FD) is distinguished by a characteristic ground-glass radiopacity that blends imperceptibly with surrounding bone and lacks a well-defined border—the two key stem features. In contrast, ossifying fibroma (a major differential) invariably presents with well-defined, corticated borders and typically a target or multilocular pattern. Osteosarcoma presents clinically with pain, rapid growth, and periosteal reaction—incompatible with this slow, painless course. Paget disease produces coarse trabecular patterns and typically occurs in older patients with systemic features. Osteoblastoma is usually well-demarcated and does not produce the characteristic ground-glass pattern. The nonmarginated, imperceptibly blending ground-glass opacification is pathognomonic for FD.

Reference: Radiographic Diagnosis of Fibrous Dysplasia in Maxilla, NCBI PMC6181250, 2018; Benign fibro-osseous lesions of the craniofacial complex. A review, PubMed 20614314, 2010, https://pubmed.ncbi.nlm.nih.gov/19292227/