Residency · Residency · Oral Maxillofacial Surgery
Benign Lesions of the Jaws: Giant Cell Lesions, Fibrous Dysplasia, and Cemento-Osseous Dysplasia
Introduction
Benign lesions of the jaws encompass a diverse group of non-odontogenic pathologies that the OMFS surgeon must accurately diagnose and manage. This lecture focuses on three important categories: giant cell lesions, fibrous dysplasia, and cemento-osseous dysplasia. Understanding the clinical, radiographic, and histologic features of each is essential for appropriate management.
| Lesion | Radiographic Appearance | Key Histologic Feature | Typical Location | Management |
|---|---|---|---|---|
| Central giant cell granuloma | Uni/multilocular radiolucency | Multinucleated giant cells + spindle stroma | Anterior mandible | Curettage (non-aggressive); resection or medical (aggressive) |
| Aneurysmal bone cyst | Expansile multilocular, "blown-out" cortex | Blood-filled spaces, no endothelial lining | Variable | Curettage (20% recurrence) |
| Fibrous dysplasia | "Ground glass," blends into normal bone | Woven bone in "Chinese letters," NO osteoblastic rimming | Maxilla > mandible | Observation; recontouring after maturity |
| Ossifying fibroma | Well-defined radiolucency/mixed, encapsulated | Woven/lamellar bone WITH osteoblastic rimming | Posterior mandible | Enucleation/resection |
| Periapical COD | Periapical radiolucency → radiopaque (stages) | Cementum-like tissue, fibrous stroma | Anterior mandible (periapical) | No treatment; teeth are vital |
| Florid COD | Bilateral radiopaque masses | Same as periapical COD | Multiple quadrants | No treatment unless infected |
Central Giant Cell Granuloma (CGCG)
Clinical Features
The CGCG is a benign but potentially locally aggressive intraosseous lesion that is more common in the anterior mandible and in patients younger than 30 years, with a female predilection of 2:1. It ranges from non-aggressive forms (slow-growing, asymptomatic) to aggressive forms characterized by rapid growth, pain, root resorption, cortical perforation, and a tendency toward recurrence.
Radiographic Features
The radiographic appearance is a unilocular or multilocular radiolucency that may cross the midline in the anterior mandible. Displacement and resorption of adjacent teeth may be observed. The CGCG may be indistinguishable from ameloblastoma or aneurysmal bone cyst on imaging alone.
Histopathology
Histologically, the CGCG consists of multinucleated giant cells in a background of ovoid to spindle-shaped mononuclear stromal cells, with hemorrhage, hemosiderin deposits, and reactive new bone formation. Importantly, the histologic appearance is identical to the brown tumor of hyperparathyroidism, so serum calcium, phosphorus, PTH, and alkaline phosphatase must be checked to exclude hyperparathyroidism.
Management
Non-aggressive lesions are treated with curettage with or without peripheral ostectomy, carrying a recurrence rate of 15 to 20%. Aggressive lesions may require en bloc resection. Medical adjuncts include intralesional corticosteroid injections (triamcinolone acetonide), calcitonin (subcutaneous or nasal), denosumab (a RANKL inhibitor with emerging evidence for aggressive CGCG), and interferon-alpha (which has an antiangiogenic effect and is reserved for refractory cases).
Aneurysmal Bone Cyst (ABC)
The aneurysmal bone cyst is an expansile, blood-filled pseudocystic lesion of bone that may occur de novo or secondary to other lesions such as CGCG or fibrous dysplasia. Radiographically, it presents as a well-defined, expansile, multilocular radiolucency with a "blown-out" cortex. Treatment is curettage, with a recurrence rate of approximately 20%. It must be differentiated from telangiectatic osteosarcoma on histology.
Fibrous Dysplasia
Pathophysiology
Fibrous dysplasia is a benign skeletal disorder caused by activating mutations in the GSNA1 gene (Gs-alpha subunit), resulting in replacement of normal bone by fibrous tissue and immature woven bone. Three forms exist: monostotic (single bone involved, 70-80% of cases), polyostotic (multiple bones involved), and McCune-Albright syndrome (polyostotic fibrous dysplasia with cafe-au-lait spots and endocrine abnormalities such as precocious puberty).
Clinical Features
Fibrous dysplasia most commonly presents in childhood or adolescence as a painless, progressive swelling of the involved bone. The maxilla is more commonly affected than the mandible in craniofacial fibrous dysplasia. It can cause facial asymmetry, orbital dystopia, and nasal obstruction. Growth typically stabilizes after skeletal maturity.
Radiographic Features
The classic radiographic appearance is a "ground glass" pattern consisting of homogeneous radiopacity with poorly defined borders that blend into normal bone. Loss of lamina dura around teeth in the affected segment is observed. CT shows fusiform expansion of bone with ground-glass density. Unlike ossifying fibroma, there is no distinct border between the lesion and normal bone.
Histopathology
Histologically, fibrous dysplasia shows irregularly shaped trabeculae of woven bone in a "Chinese letters" or "alphabet soup" pattern within a cellular fibrous stroma. Critically, there is no osteoblastic rimming of the bony trabeculae, which distinguishes it from ossifying fibroma.
Management
Asymptomatic, non-progressive lesions are observed. Surgical recontouring (osteoplasty) is performed for aesthetic or functional concerns, ideally after skeletal maturity. Resection should be avoided unless malignant transformation is suspected, which occurs in less than 1% of cases. Bisphosphonates have been used with variable results for pain control. Regular clinical and radiographic follow-up is necessary, and biopsy is indicated if rapid growth, pain, or radiographic change suggests malignant transformation to osteosarcoma.
Cemento-Osseous Dysplasia (COD)
Classification
Cemento-osseous dysplasia is classified into three types: periapical cemento-osseous dysplasia (periapical COD), which is confined to the periapical region of the anterior mandible and most commonly affects middle-aged Black women; focal cemento-osseous dysplasia, which presents as a single posterior lesion; and florid cemento-osseous dysplasia, which involves multiple quadrants and is often bilateral.
Clinical and Radiographic Features
The associated teeth are vital (positive pulp testing), which is the key distinguishing feature from periapical pathology. Three radiographic stages are recognized: the osteolytic (early) stage presents as a periapical radiolucency mimicking periapical pathology, the cementoblastic (intermediate) stage shows a mixed radiolucent-radiopaque pattern, and the mature stage presents as a dense radiopaque mass with a radiolucent border. Unlike fibrous dysplasia or ossifying fibroma, there is no expansion of cortical plates.
Management
No treatment is required in most cases, as this is a reactive process rather than a neoplasm. Biopsy or surgery should be avoided unless secondary infection occurs, because the avascular cementum-like tissue is prone to infection if exposed. Vitality testing of associated teeth is critical to avoid unnecessary endodontic treatment. The lesion is monitored radiographically. Antibiotic therapy is provided for secondary infection, and limited debridement is performed if sequestration occurs.
Clinical Pearls
Serum calcium, PTH, and alkaline phosphatase should always be checked when diagnosing a giant cell granuloma to rule out brown tumor of hyperparathyroidism. Fibrous dysplasia shows no osteoblastic rimming on histology, which distinguishes it from ossifying fibroma. Cemento-osseous dysplasia requires no treatment in most cases, and surgical intervention risks secondary infection. Pulp vitality testing is essential to differentiate periapical COD from periapical pathology. Aggressive CGCG may respond to medical therapy (intralesional steroids, calcitonin, denosumab) prior to or instead of surgical resection.
References
- de Lange J, van den Akker HP, van den Berg H. Central giant cell granuloma of the jaw: a review of the literature with emphasis on therapy options. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2007;104(5):603-615.
- DiCaprio MR, Enneking WF. Fibrous dysplasia: pathophysiology, evaluation, and treatment. J Bone Joint Surg Am. 2005;87(8):1848-1864.
- Summerlin DJ, Tomich CE. Focal cemento-osseous dysplasia: a clinicopathologic study of 221 cases. Oral Surg Oral Med Oral Pathol. 1994;78(5):611-620.
- Chrcanovic BR, Reher P, Sousa AA, Harris M. Ostectomy in the management of central giant cell lesions of the jaws. J Oral Maxillofac Surg. 2012;70(11):2508-2516.