What is a Fibro-Osseous Lesion?
A fibro-osseous lesion is a benign pathologic process of bone characterized by the replacement of normal bone architecture with fibrous connective tissue containing varying amounts of mineralized material (bone or cementum-like tissue). 1, 2
Core Definition and Characteristics
Fibro-osseous lesions (FOLs) represent a heterogeneous group of disorders that share similar microscopic features: hypercellular fibroblastic stroma composed of fibroblasts and collagen, containing various combinations of bone, cementum-like tissue, and other calcified structures. 1, 2 These lesions are relatively common in the craniofacial complex, particularly the jaws. 3
Classification Categories
The main categories of benign fibro-osseous lesions include:
- Developmental lesions 2, 4
- Reactive (dysplastic) processes - including cemento-osseous dysplasia 4
- Neoplastic lesions - such as ossifying fibroma 4
- Dysplastic conditions - including fibrous dysplasia 4
Most Common Specific Entities
The three most frequently encountered fibro-osseous lesions are:
- Cemento-osseous dysplasia (45% of cases in recent series) 5
- Ossifying fibroma (39% of cases) 5
- Fibrous dysplasia (16% of cases) 5
Diagnostic Approach
Accurate diagnosis requires correlation of clinical presentation, radiographic imaging, and histopathologic features - no single modality is sufficient alone. 5, 1, 4
Key Diagnostic Features to Assess:
- Patient demographics: Age, sex (females predominantly affected at 73%), and location (86% occur in mandible) 5
- Radiographic appearance: CT demonstrates characteristic ground glass density of fibro-osseous lesions and best depicts lesion mineralization 6
- Histopathology: Most cases (95%) require biopsy for definitive diagnosis, as imaging features alone are rarely pathognomonic 5
Imaging Characteristics
On CT imaging, fibro-osseous lesions demonstrate:
- Ground glass density - a characteristic radiographic finding 6
- Osseous matrix mineralization patterns that help distinguish these lesions from other bone pathology 6
- Variable bone remodeling depending on the specific type and biological activity 6
CBCT is the diagnostic imaging technique of choice (68% of cases), followed by panoramic radiography (18%). 5
Clinical Significance
While these lesions are benign, proper categorization is essential because treatment varies significantly by specific diagnosis - ranging from observation alone to surgical intervention. 2, 4 The challenge lies in distinguishing between entities that share overlapping histopathologic features but require different management approaches. 1, 3