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Fibrous Dysplasia — MFDS Part 1 MCQ

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ModerateOral PathologyFibrous DysplasiaMFDS Part 1

A 19-year-old patient presents with slowly progressive, painless unilateral expansion of the maxilla. Which radiographic appearance would most strongly support a diagnosis of fibrous dysplasia?

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Correct answer: E — Diffuse ground-glass opacity with an ill-defined transition blending into adjacent bone

Fibrous dysplasia most characteristically produces a diffuse, expansile ground-glass opacity whose poorly defined margin blends gradually into adjacent normal bone. This reflects replacement of normal bone by fibro-osseous tissue and supports option E in this young patient with painless maxillary expansion. A sharply corticated unilocular radiolucency is more typical of a cyst. A well-defined soap-bubble lesion with root resorption suggests ameloblastoma. Generalised cotton-wool change accompanied by loss of the lamina dura and hypercementosis favours Paget disease, although fibrous dysplasia can occasionally show less typical mottled appearances. A sunburst periosteal reaction with cortical destruction and soft-tissue extension raises concern for osteosarcoma.

Reference: Davidova LA, Bhattacharyya I, Islam MN, Cohen DM, Fitzpatrick SG. An Analysis of Clinical and Histopathologic Features of Fibrous Dysplasia of the Jaws: A Series of 40 Cases and Review of Literature. Head and Neck Pathology. 2020;14:353–361. https://pubmed.ncbi.nlm.nih.gov/31079311/