A 25-year-old woman presents with progressive facial asymmetry. CT of the facial bones shows a diffuse expansile lesion of the right maxilla with a 'ground glass' matrix and poorly defined margins blending into normal bone. The most likely diagnosis is:

• A Osteosarcoma
• B Paget disease
• C Osteoblastoma
• D Fibrous dysplasia ✓

Explanation

Fibrous dysplasia classically presents as an expansile lesion with ground glass matrix, indistinct margins blending into adjacent normal bone, and no periosteal reaction. It commonly affects the maxilla and craniofacial bones in young adults. Osteosarcoma shows aggressive features with periosteal reaction and cloud-like osteoid. Paget disease occurs in older patients and shows cortical thickening with a cotton-wool appearance.

Reference: Diagnostic Imaging: Musculoskeletal Neoplasms, 2nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.