Fibroosseous

Fibroosseous is a term used in pathology and dentistry to describe a group of bone lesions characterized by the replacement of normal bone tissue with a mixture of fibrous connective tissue and immature bone. These lesions are not true neoplasms, meaning they do not arise from uncontrolled cell growth, but rather represent abnormal bone development. The microscopic appearance is one of irregular woven bone trabeculae embedded within a cellular fibroblastic stroma.

The most common type of fibroosseous lesion is fibrous dysplasia, where bone development is arrested in a disorganized state. Another example is ossifying fibroma, which is a benign tumor-like lesion composed of fibrous tissue and varying amounts of calcification and bone formation. Periapical cemental dysplasia, found around the apex of teeth, is also considered a fibroosseous lesion.

Clinically, fibroosseous lesions can present as asymptomatic swellings or may cause pain, facial asymmetry, or tooth displacement depending on their size and location. Radiographically, they typically appear as radiolucent or mixed radiolucent-opaque lesions with a characteristic ground-glass or wispy appearance. Treatment depends on the specific type of lesion, its size, and the presence of symptoms, and can range from observation to surgical excision. These lesions are typically benign, though rare malignant transformations have been reported in association with some types, particularly fibrous dysplasia.