A peripheral giant cell granuloma (PGCG) is a localized hyperplastic gingival enlargement. It is an intermittent oral lesion that originates in interdental tissues, periosteum or periodontal membranes[1]. PGCG is caused by regional irritation or chronic trauma due to sub-gingival plaque and calculus[2-4]. PGCG presents as a smooth-surfaced nodule, that is red, purple or blue[4,5]. Surgery is required to excise lesions, and occasionally there is a requirement for subsequent grafting[2,6]. The lesion recurrence rate is approximately 10%; however, multiple recurrences with inevitable loss of the adjacent teeth are a potential complication. In children, PGCGs grow rapidly within several months of the initial diagnosis[2].

A 6-year-old female attended the Department of Pediatric Dentistry at Yonsei University with swelling on the palatal marginal gingiva of the upper right central incisor. An operculectomy was performed in a local clinic to correct the delayed eruption of the upper right central incisor; however, gingival swelling remained following tooth eruption. The patient had good oral hygiene with no systemic disease or family medical history.

Upon intra-oral examination, a solitary exfoliated lesion was observed on the palatal gingiva of the upper right central incisor (Fig. 1). Tenderness was observed upon palpation and hemorrhaging occurred readily. The affected tooth was dislocated distolabially.

An intra-oral periapical radiograph (Fig. 2) failed to reveal abnormal pathology.

No changes to the lesion were observed within 2 weeks following surgery, and a 0.9 × 0.4 × 0.2 cm³ excisional biopsy was performed under local anesthesia. A histological evaluation using light microscopy revealed multinucleated giant cells within a cellular, well-vascularized mesenchymal proliferation (Fig. 3). The histological diagnosis was giant cell granuloma.

During the 1-year follow-up period, no significant changes were observed. Spontaneous closure of the space between the central incisors was observed and the maxillary right central incisor aligned within the anterior maxillary arch (Fig. 4, 5).

Jaffe[7] first coined the term “giant-cell reparative granuloma” for a central lesion in the jaw bones. Bernier and Cahn[8] used the term “peripheral giant cell reparative granuloma” to describe peripheral lesions. The etiology of PGCG is unknown[ 4], but it is generally accepted that the term originated to describe regional irritation or trauma - due to calculus, periodontal disease, periodontal surgery, food impaction, orthodontic appliances, or defective restorations with overhanging margins, ill-fitting removable appliances, or implants[8-10].

PGCG occurs in individuals of all ages[11]; however, the most widely affected individuals are those in their fourth[4] to sixth[12] decades of life. PGCG also varies in terms of oral location; with occurrence in the posterior region and mandible being more common than in the anterior region and maxilla[4,11-13]. PGCG lesions form in the interdental papilla of dentate areas, as well as the edentulous alveolar margin and marginal gingival levels[2,6,13].

PGCG lesions are firm, soft, bright, pedunculated, or sessile nodules of varing size, with most being less than 2 cm in diameter[2]. The lesions are red, purple, or blue appear with and ulcerated surface[12]. They are not painful and growth is induced by chronic trauma.

Since PGCG is a soft tissue lesion, the underlying bone is rarely affected. Radiography is used to determine the size and origin of lesions, as well as to reveal superficial erosion or cupping of the crest of the interdental bone or alveolar bone margins[2]. Widening of the periodontal ligament and tooth mobility may also be seen on radiographs[3]; however, such traits are not always present in PGCG cases[12].

Lester et al.[12] and Katsikeris et al. [4] suggested the histology used to diagnose PGCG. A nodular proliferation of mesenchymal tissue with abundant multinucleated giant cells covered by stratified squamous epithelia, as well as stromal cells consisting of plump spindle-shaped and ovoid mesenchymal cells with variably sized nuclei are the primary features. Abundant capillaries, inflammatory cells, hemorrhaging, and hemosiderin are also indicative of PGCG. In the present case, cellular, vascular and fibrous stroma containing scattered mitotic figures were observed.

Since the clinical appearance of PGCG is similar to that of several other lesions, differential diagnosis is necessary. Central giant cell granulomas (CGCGs) have a similar histology to PGCGs; however CGCGs are aggressive, intraosseous lesions[11]. Additionally, CGGs are painful and cause bone and dental root resorption, necessitating radiological analyses to distinguish between PGCGs and CGCGs.

PGCG must also be differentiated from pyogenic granulomas, parulis, peripheral ossifying fibromas and hemangiomas[2,12]. Pyogenic granulomas do not cause alveolar bone loss, nor do they disturb tooth positioning. Parulis is caused by entrapped foreign bodies or non-vital teeth. The occurrence of pain and purulent exudate enable differentiation of parulis from PGCG. Peripheral ossifying fibromas rarely occur in children, and are not purple or blue. Occasionally, however, peripheral ossifying fibromas exhibit small calcified foci upon radiographic examination. Hemangioma causes rapid hemorrhaging, increased tissue, temperature and blanching upon palpation. Fatima et al.[15] reported that PGCGs were misdiagnosed 89% of the time; thus, clinical, radiographic, and histopathologic evaluations are required for correct diagnosis[16].

Treatment of PGCG requires complete surgical excision[12] and the prevention of irritating factors[13]. Incomplete excision, which occurs in approximately 10% of cases caused regrowth[4,13]; therefore, postoperative evaluations are necessary for early detection.

The present case was notable since PGCG occurred in the maxilla, and was associated with the eruption of a maxillary central incisor. In children, reactive gingival lesions, including PGCGs, grow rapidly within several months following diagnosis. Lesions can resorb bone, interfere with tooth eruption, and cause tooth movement[3]. Therefore, early diagnosis of PGCG in necessary for adequated management and the prevention of tooth and bone loss.

PGCGs are reactive, exophytic gingival growths, caused by irritation or trauma from subgingival plaque and calculus. In the case described here, PGCG was associated with the eruption of a maxillary central incisor. Soft tissue lesions occuring in the oral cavity of children require early detection, treatment and routine evaluations to prevent recurrence and ensure normal tooth eruption and well-aligned dentition.