Fibro-osseous lesion composed of a moderately cellular, collagenous stroma containing uniform spindle cells without cytological atypia or mitotic activity. Embedded within the stroma are irregular, curvilinear trabeculae of woven bone lacking osteoblastic rimming, forming classic "Chinese character" configurations. The vascularized stroma shows no evidence of necrosis or malignancy.
Rt. maxillary lesion, suspected fibrous dysplaaia.
Bone fragments collectively measured 4.5x3.8x1 cm, with separate 4 teeth.
Maxillary lesion, excision:
COMMENT
According to the World Health Organization classification of head and neck tumors, fibrous dysplasia is a benign, non-neoplastic fibro-osseous process linked to post-zygotic somatic activating GNAS gene mutations. The lesion is typically slow-growing and self-limiting, usually stabilizing following skeletal growth cessation. Malignant transformation is extremely rare, occurring in less than one percent of cases. Radiotherapy is strictly contraindicated as it significantly increases the risk of secondary malignant transformation.