Journal of Advances in Medicine and Medical Research

Background: Polyostotic fibrous dysplasia is an uncommon fibro-osseous skeletal disorder driven by postzygotic GNAS1 mutations; although its general pathology is well described, site-specific histopathological data from surgical cohorts in Central Asia remain limited.

Aims: To describe the histopathological features in surgical specimens from patients with polyostotic fibrous dysplasia and to correlate the findings with clinical complications.

Study Design: Retrospective histopathological study of surgical specimens.

Place and Duration of Study: Department of Pathological Anatomy, Samarkand State Medical University, using operative specimens from patients treated at the Samarkand branch of the Republican Specialised Scientific Practical Centre for Traumatology and Orthopaedics, between 2020 and 2025.

Methodology: Forty-eight surgical specimens were fixed in formalin, paraffin-embedded, sectioned at 5–7 µm, and stained with haematoxylin-eosin, Van Gieson’s, and Weigert’s methods.

Results: Light microscopy consistently showed replacement of medullary bone by fibrous stroma with haphazardly arranged collagen bundles, producing the classic curvilinear, ‘Chinese-letter’ pattern of woven-bone trabeculae. Dystrophic calcification at lesion margins, cortical thickening, myxoid microcysts, thin-walled stromal vessels, and foamy xanthoma cells were identified. Multinucleated giant-cell clusters resembling a giant-cell tumour were present in selected specimens. Pseudoarthrosis with attenuated periosteal sclerosis occurred in two patients (4.2%).

Conclusion: Young individuals were disproportionately affected. The dominant finding was fibrous replacement of bone with peripheral calcification and focal giant-cell aggregates, predisposing to pathological fracture and pseudoarthrosis.