Central Giant Cell Granuloma

Synonym / Acronym

Giant cell reparative granuloma / CGCG

Definition

Central giant cell granuloma is a fairly common lesion in the jaws. It is a benign reactive lesion rather than benign neoplastic lesion. The etiology is still completely unknown but thought to be of a reactive process to some unknown stimuli. However, it has radiographic features similar to neoplastic lesions. CGCG is characterized by the presence of multinucleated giant cells, fibrous tissue, vascular channels and macrophages. The relationship of CGCG to giant cell tumor of long bones is still unclear and controversial.

Clinical Features

Central giant cell granuloma affects young people; it can occur in the first three decades of life and in 60% of cases less than 20 years old. The lesion is usually presents as painless growing mass with possibility of displaced or mobile teeth. The color of the overlying mucosa can be purple. It is usually detected as incidental finding during routine dental examination. CGCG usually grows slowly and sometimes quickly. Central giant cell granuloma can be observed anywhere in the mandible and occur most frequently in the anterior mandible.

Radiographic Features

Central giant cell granuloma appears as poorly defined unilocular radiolucency or multilocular radiolucency with scalloped borders. The lesion occurs usually anterior to the first molar; however, large lesions can extend posterior to the first molar. Lesions that occur in the maxilla can be aggressive and invasive resembling malignant tumors. One of the key features of CGCG is its ability to cross the midline of the mandible. Small lesions can appear totally radiolucent, granular, or with wispy septa representing thin radiopaque lines of fine bone are present that looks like wispy septa; giving the lesion its multilocular appearance. Giant cell granuloma usually destroys the lamina dura and causes roots resorption and displacement of teeth. The root resorption is usually irregular when compared to the smooth roots resorption occurring with cysts; and resorption is not a regular feature. CGCG has great potential for expansion and causes thinning of cortical boundaries. The outer cortex may show undulating expansion. In rare cases, it can cause perforation of the outer cortex especially in recurrent lesions in the maxilla.

Differential Diagnosis

Given signs of expansion of central giant cell granuloma, and if septa are present, the lesion may look similar to other lesions. Our differential list should include ameloblastoma, odontogenic myxoma, and aneurysmal bone cyst. In contrast, ameloblastoma tends to occur in older age group, posterior in the mandible, and have well-defined, curved septa; whereas, CGCG has wispy ill-defined trabeculation. Odontogenic myxoma does not cause much expansion, occurs in older age group, and has well-defined septa. Although aneurysmal bone cyst looks radiographically very similar to CGCG especially the appearance of its septa; however, ABC is a rare entity, causes extensive expansion and it is found in the posterior mandible. COF can be included in the differential diagnosis when granular internal architecture is present. A small radiolucent CGCG can look similar to a simple bone cyst. Radiologic and histologic characteristics of CGCG may look similar to brown tumors associated with hyperthyroidism.

Treatment

Cone Beam CT is the modality of choice to evaluate the location and the extension of the lesion to its surrounding structures especially in cases of large lesions as they tend to destroy the outer cortex. Presence of hyperparathyroidism should be done though serum testing for elevated calcium or parathormone levels if the lesion occurred after second decade of life.
Enucleation, curettage and jaw resection is the treatment of choice for CGCG. Close follow-up is recommended as CGCG has the tendency for recurrence. Recurrence can occur in the maxilla but it is rare.

Case Reports

HISTORY: A 17-year-old male was referred for a Cone Beam CT scan for assessment of healing and possible recurrence s/p excision of histologically confirmed central giant cell granuloma.


FINDINGS: There are four foci of radiolucency in the anterior mandible. There is a lesion approximately 5 mm in diameter lesion located at the linugal aspect of the alveolar crest in the region of teeth #28, 29. The lesion can be seen on cross-sections 1-4. Going from cross-sections 5-9 we can see another lesion just below the first lesion. It measures approximately 12 mm in diameter. Another lesion can be seen in the midline and it is represented by cross sections 12-18. This lesion appears to have thinned and may have perforated the alveolar crest. An additional solitary lesion approximately 5 mm in diameter can be seen in the area of tooth #21. Thinning and possible perforation of the alveolar crest is present. It is worth to mention that the radiolucency in the center of the mandible in cross-section 21 represents the mental foramen.


IMPRESSION: In the light of previous post-surgical panoramic image of CGCG, the current radiographic signs suggest recurrence of CGCG at multiple locations in the anterior mandible. Occlusal and cross-sectional images confirm expansion and thinning of the facial cortex in the area of tooth #27.


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