Gingival cyst of the adult in a pediatric patient: Report of a case

Abstract Although the gingival cyst of the adult is considered rare in children, it can occur. The GCA can cause necrosis of the alveolar bone if untreated and should be considered in the differential diagnosis of raised gingival lesions.


| CASE REPORT
The patient, a healthy boy of Asian ethnicity, first presented to the dental clinic in August 2016 at the age of 3y10m. At his routine dental exam in August 2017, a "small inflamed area" was noted near tooth #Q (FDI #82). A periapical radiograph obtained that day showed a subtle radiolucency near the mesial aspect of the periodontal ligament space of tooth #Q (FDI #82) ( Figure 1). The decision was made to monitor this area. It was noted again in March 2018 as possibly traumatic in origin. Later in March 2018, the patient was brought in for a limited examination for the "sore" near tooth #Q (FDI #82). Per the patient's father, the area had been very stable and he had noticed no change. It was noted that based on clinical appearance the lesion may have been a fibroma. At the next routine dental examination in September 2018, the lesion remained present and unchanged (Figure 2). At that point, a differential diagnosis of: gingival cyst, hemangioma, pyogenic granuloma, or peripheral giant cell granuloma was established. After discussion with the patient's father, the decision was made to take the child to the operating room for surgical excision and biopsy due to the need to reflect a mucoperiosteal flap to remove the lesion in its entirety, the child's young age, and the risk that cooperation would deteriorate during the procedure.
The patient was taken to the operating room in October 2018. General anesthesia was induced, a nasotracheal tube was placed and secured, and a throat pack was placed. About 1cc of 2% lidocaine with 1:100K epinephrine was infiltrated. A #15 scalpel was used to do a full-thickness mucoperiosteal flap, which was elevated and reflected. The lesion was identified as a round well-circumscribed (encapsulated) gray mass with a soft texture. The surface was smooth and extended into the cortical bone. The lesion was removed in two fragments and submitted for microscopic examination ( Figure 3). The cortical bone was curetted. The surgical wound was closed with 1 horizontal mattress and 2 interrupted 3-0 chromic gut sutures. The patient was extubated, monitored in PACU, and discharged uneventfully. He presented for postoperative evaluation one week later. Healing was uneventful and satisfactory ( Figure 4).
The biopsy report noted: The biopsy report made mention of teeth numbers R and S; however, this was likely a typographical error since the lesion was located between teeth numbers Q and R (FDI #82 and #83). A dentigerous cyst (the other lesion to be named on the differential diagnosis) is not very likely due to the unaggressive and stable nature of the lesion as demonstrated through chart notes.
The child continued to be a regular dental attender. The healing at approximately 10 months postsurgery was within normal limits. No recurrence was noted as of publication date.

| DISCUSSION
Several etiologic possibilities of the GCA were discussed by Ritchey and Orban. These include heterotopic glandular elements or epithelial remnants or the enamel organ, periodontal ligament (membrane), or dental lamina. Epithelial remnants may also migrate from the surface epithelium as a degenerative epithelial peg or proliferation from trauma. 6,7 A distinction should be made between the gingival cyst and the lateral periodontal cyst on the basis of cell origin. Lateral periodontal cysts arise from the periodontal ligament. 8,9 However, the distinction has been contested by Wysocki and Brannon. 10 Both cysts display glycogen-rich clear-cell rests of dental lamina, suggesting a histogenetic link between the GCA and the lateral periodontal cyst. There is also a coexistence of features such as enlargement and cystic degeneration with microcyst formation in the clear-cell rests of dental lamina, focal thickenings (plaques) composed of clear cells in the epithelial lining, and a thin epithelial lining exhibiting varying numbers of clear cells. The WHO classifies these cysts as separate; however, both are considered developmental odontogenic cysts. 5 Gingival cysts are generally <1 cm possibly due to the fact that they arise from postfunctional cells of the dental lamina. The prevalence of gingival cysts in adults has been reported as 0.3% of all odontogenic cysts. 11 They are generally slow-growing asymptomatic oval or round lesions in the attached gingiva. They may appear as radiolucent due to pressure atrophy of the subjacent alveolar bone. Less than 20% of cases described in the literature presented with a radiographic finding. 12 Although these lesions are slow growing, excisional biopsy is the treatment of choice. If the lesion is not removed via excisional biopsy, it could potentially progress and cause pressure necrosis of the alveolar bone. Biopsy is also indicated to rule out other gingival lesions on a differential diagnosis. Since young children may not be able to tolerate an excisional biopsy in the dental setting, general anesthesia or sedation may be indicated. This is the third reported case of a gingival cyst of the adult appearing in a pediatric patient. Although gingival cyst of the adult is thought to be rare in the pediatric population, it is prudent to consider gingival cyst in the differential diagnosis in a pediatric patient for gingival lesions that do not resolve spontaneously, especially those arising in the anterior mandible to first primary molar area.

| SUMMARY
• Gingival cyst of the adult is rare in children but should be considered for raised gingival lesions in the anterior mandible. • If untreated, a GCA may result in pressure necrosis of the alveolar bone. • The GCA is best treated with excisional biopsy, and recurrence is rare.