What Is Central Giant Cell Granuloma?
Central giant cell granuloma (CGCG) is an uncommon histologically (microscopically) benign (non-cancerous) tumor. It is a clinicopathologic entity that affects the jaw bones. Locally, the lesions of CGCG are highly aggressive and clinically destructive. These lesions are of osteoclastic origin (osteoclasts are bone-resorbing cells) that occur mainly in the orofacial region, especially the jaw. Clinically, they present as a single lesion. On a radiograph (X-ray), they can appear as a multilocular (having multiple cavities) radiolucency (a dark area in a radiograph) with scalloped margins. The other appearances are honeycomb or soap bubble-like. CGCG accounts for less than 7 percent of all benign tumors of the jaws. These affect the mandible more in comparison to the maxilla. In the mandible, the primary areas of involvement are the body, anterior (in front) to the first molars.
What Is the Etiology and Histopathology of Central Giant Cell Granuloma?
CGCG was previously considered a reactive lesion. However, it has unpredictable and occasional aggressive behavior and an association with long bone tumors and syndromes. Therefore, it is denoted a benign neoplasm. Also, many CGCG cases are reported in patients with genetic mutations. Nearly 62 percent of granulomas (granuloma is a collection of white blood cells) are only localized to the jaw while retaining the benign nature and limited progression if diagnosed early. However, many lesions become aggressive with typical osteolytic (degeneration of bone) spread. The spread is a fibrous tissue proliferation with hemorrhage (bleeding) and hemosiderin (a pigment derived from the breakdown of red blood cells) deposits and osteoclast-like giant cells (inflammatory cells) with reactive bone formation.
What Are the Clinical Features and Recurrence Rate of Central Giant Cell Granuloma?
CGCG frequently affects younger patients under the age of 30. However, global statistics show that around 80 percent of CGCG patients are diagnosed under 20. Further, there is a notable female predilection. Clinically, CGCG has a variable behavior. Also, it can be diagnostically challenging if not detected on time. For instance, many patients with CGCG show asymptomatic, indolent, and slow growth. However, with time, the lesions may get aggressive and undergo a rapid hollowing out of bone. It further leads to the expansion, thinning, and perforation of the jaw cortical plates (bony plates) along with root resorption of the adjacent tooth/teeth. When the lesions aggravate, most of the adjacent structures such as nerves are displaced by the tumor. As a result, it manifests as moderate to severe pain in the affected individuals. Perineural invasion (around the nerve) and infiltration into the adjacent soft tissues are not seen in these tumors. Therefore, CGCG can expand and displace adjacent structures, rather than invading or infiltrating them (in contrast to the other jaw tumors). CGCG is also associated with a relatively high recurrence rate. Almost 15 to 20 percent of the lesions recur. Furthermore, the more extensive the lesion, the higher the chances of recurrence noted.
Why Is Differential Diagnosis of Central Giant Cell Granuloma Challenging?
The dentist must establish a correct diagnosis of bone tumors in the orofacial region. It is because many bone tumors that affect the jaw bones have similar clinical features. The differential diagnosis (a diagnosis that differentiates conditions with similar features) for CGCG is:
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Aneurysmal bone cyst (a benign and expansile blood-filled cavity).
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Ameloblastoma (a jaw bone tumor that originates from the tooth germ).
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Ossifying fibroma (a benign tumor in which the normal bone is replaced by fibrous tissue).
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Odontogenic myxoma (a benign tumor that originates from connective tissue).
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Sarcomas (soft tissue tumors).
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Arteriovenous malformations (an aberrant connection between an artery and vein).
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Infectious granulomas (form in response to infection, inflammation, or irritants).
These cysts and tumors also present with a soap bubble or honeycomb appearance with a scalloped margin which can be a diagnostic challenge to the oral radiologist. It is also crucial to differentiate the lesions from oral malignancies (cancers) of hematopoietic (blood-forming) tissue or lymphoid tissue (structures that support immunity) origin. Many cancers affecting the oral and maxillofacial locations, such as the tonsils (55 percent of jaw tumors ) and palate (30 percent of jaw tumors), are differential diagnoses for CGCG. Hence, they need correct identification at early stages as they carry a poor prognosis for the patient.
What Is the Management of Central Giant Cell Granuloma?
Based on the clinical characteristics and the behavior of CGCG, the oral surgeon can consider the following options.
1. Curettage- Curettage is the scraping of the inner lining of the lesion. It is the gold standard for CGCG treatment.
2. Surgical Excision- Complete removal is advocated in multiple recurrences or extensions to adjacent tissues.
3. Cryotherapy- Cryotherapy (cold therapy) is used to freeze and destroy abnormal tissue. Combined curettage and cryotherapy may reduce the recurrence rate of CGCG compared to the curettage used as the treatment.
4. Radiation- Radiation has been used as a modality for CGCG, but sarcoma development has been reported in some patients.
5. Newer Treatments:
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Platelet-rich Fibrin- Platelet-rich fibrin (PRF) is a new generation of platelet concentrate isolated from blood. It is a rich source of growth factors delivered in high concentrations to the bone defect site.
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Tissue Engineering- It is a scientific method involving cells, engineering, and suitable biochemical factors to restore different types of biological tissues. In CGCG, augmentation of the bony cavity after surgery is beneficial for functional and esthetic rehabilitation.
Conclusion
Early and correct diagnosis of CGCG can yield a good prognosis for the patient. However, a multidisciplinary approach is needed for CGCG management as the lesions are difficult to differentiate from other pathologies. Still, there are significant advances in understanding and managing this enigmatic group of lesions.
