Fibrous dysplasia progression in patients with craniofacial involvement of the frontal and zygomatic bones

Authors

  • JE Freeman
  • II Elbashir
  • KS Pan
  • AM Boyce

Abstract

Fibrous dysplasia (FD) is characterized by expansile fibro-osseous lesions that may occur in association with endocrinopathies as part of McCune-Albright syndrome (MAS). This study aimed to evaluate expansion rates in craniofacial lesions associated with significant morbidity, including the frontal bone and zygomas. Patients with craniofacial FD and serial CT imaging from a natural history study were evaluated. Volumetric analyses of CT scans were performed using MIM Encore. Generalized mixed model analysis accounted for intra-subject correlation, with FD lesion volume as the dependent variable. In addition to age, effects of MAS-associated endocrinopathies, sex, skeletal disease burden, and history of bisphosphonate treatment were evaluated. 64 total lesions (frontal N =28, zygomatic N=36) in 33 patients were assessed longitudinally in serial CT scans. Frontal and zygomatic lesion volume increased with age (p<0.001), and expansion rate decreased over time (p<0.001). There were no associations between expansion rates and MAS-associated endocrinopathies, sex, skeletal disease burden, or bisphosphonate treatment. Frontal FD lesions expanded at the greatest rate (5.19 cm3/year, 95% CI 4.33–6.05, p<0.001). Craniofacial lesion expansion rates are most rapid in younger children and decline as patients approach adulthood. FD lesions involving the frontal bone expand at greater rates than other facial bones including the zygomata and previously characterized gnathic lesions. These findings indicate that location-specific analyses are required for the assessment of FD progression.

Scientific Focus Area: Clinical Research

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