Clinical picture, diagnosis, and treatment of gingival cyst: A narrative review

Introduction

Gingival cyst (GC) (Figures 1 and 2) is a very rare [1-15] pathological phenomenon, with extraosseous occurrence [4] in the anterior and posterior parts of oral cavity, in both the maxilla and mandible [4, 14]. As this type of cyst is very occasional among odontogenic cysts, its description is not very detailed, and often mentioned together with other more common odontogenic cysts [4, 14]. GC is most commonly located on the mandibular buccal or labial gingiva in the area of incisors, cuspids, and bicuspids [1-12, 14-21], in interdental papilla [5], and free and/or attached gingiva [2, 5]. GC usually affects patients aged between 40 and 60 years [1-10, 12-15, 17-21]. According to Viveiros et al. [14] study, the rate of occu­rrence is 53% in the mandibular and 40% in maxillary anterior parts. In Nxumalo and Shear [10] retrospective study (14 cases), where other studies were included for comparison, i.e., Reeve et al. (4 cases), Buchner et al. (26 cases), and Wysocki et al. (8 cases), the rate of occurrence in all 52 cases was presented as 73% (38 cases) in the mandible and 27% (14 cases) in the maxilla. Sato et al. [12] presented nearly 4 : 1 mandible-to-maxilla ratio. Whereas Chrcanovic et al. [4] reported GC occurrence in 76.5% of cases (n = 114) in the mandible, and in 23.5% of cases (n = 35) in the maxilla, from an overall 157 cases. Buchner et al. [2] demonstrated 73% of cases in the mandible and 27% in the maxilla (33 cases). Wysocki et al. [15] observed 70% of cases in the mandible, 10% of the ma­xilla, and 20% of unknown (10 cases). Villasis-Sarmiento et al. [21] reported a 1 : 1 mandible-to-maxilla ratio in 4 cases. Furthermore, these case reports [1, 3, 5-9, 11, 16, 17, 19, 20] have also shown the cuspid-bicuspid area in the mandible as the main site of occurrence. There was a single-case report from Schulz et al. [13], who mentioned a maxillary occurrence of GC in edentulous area.
Concerning predilection to gender; 1 : 1.3 male-to-female ratio was reported by Sato et al. [12], while 65% of females and 35% of males were presented in a study by Viveiros et al. [14]. Villasis-Sarmiento et al. [21] showed 100% of female predilection in 4 cases. Varius studies mentioned female predilection [1, 3-6, 11] and male predilection [7-9, 13, 15, 19]. Also, Nxumalo and Shear [10] demonstrated 57% and 43% occurrence rate in males and females, respectively. However, Eversole [17] and Tolson et al. [20] have not reported any predilection to sex. Therefore, depending on the number of cases analyzed in a particular study, the predilection may vary from highly predilected (lower number of cases analyzed) [21] to more evenly distributed between genders (higher number of cases analyzed) [4, 14]. Overall, a slightly higher incidence in females [18] was observed.
Moreover, racial predisposition to GC is present to some extent. Mainly Caucasians are the ones predisposed to developing this type of cyst [2 ,4, 11-14, 19], while African Americans and Asians are less affected [2, 3, 12-14, 19]. Several authors stated predilection to race [8, 19], while others did not indicate any predilection to race [1, 4, 6, 9, 10, 15, 18, 20, 21]. According to a study done by Viveiros et al. [14], there were 60% of Caucasians (12 cases), 20% of African Americans (4 cases), and 5% of Asians (1 case). Buchner et al. [2] showed 85% of Caucasians (28 cases), 12% of African Americans (4 cases), and 3% of Asians (1 case). Additionally, Cairo et al. [3] presented 3 Caucasian cases (100%).
The incidence of GC is very low, based on studies by Giunta [18] (0.08%), Buchner et al. [2] (0.15%), Viveiros et al. [14] (0.3%), and Villasis-Sarmiento et al.    [21] (0.5%). This can be due to the fact that only half of GC cases are diagnosed properly [18]. From these data, the occurrence rate can be presented as less than 0.5%. While the documented recurrence rate of GC was 3.2%, according to Chrcanovic et al. [4]. Other authors did not show any recurrence rates of GC [1-3, 5, 7-19, 21, 22], while some presented a rare chance for recurrence [6, 20].
The aim of the current review was to summarize knowledge about the etiology, symptoms, diagnosis, and treatment available in scientific literature.

Material and methods

PubMed and Google Scholar databases were used as sources. The following key words and their combinations: “gingival cyst” and “odontogenic cysts” were applied to obtain the list of available references. No exclusion criteria were used for the initial search. This review encompassed clinical trials, both randomized and non-randomized studies, classic and comparative research, multi-center and in vivo studies, case reports, longitudinal studies, and literature reviews.

Results

The literature on GC of adults indicated that this rela­tively uncommon developmental odontogenic cyst is most frequently observed in individuals aged between 50 and 60 years. It was predominantly found in the mandible, particularly in the canine-premolar regions, usually appearing as a solitary lesion approximately 5 mm in diameter, typically treated with excisional biopsy. Histological examination revealed a very thin, uninflamed wall, lined with a squamous or cuboidal epithelium. The occurrence of multiple cysts is extremely rare.

Discussion

Gingival cyst is of odontogenic origin [2, 7, 15, 20, 22-27], and emerges from the remnants of the dental lamina glands of Serres [2, 15, 22-24, 26, 27], the epithelial remains of Malassez, and the reduced enamel epi­thelium [6, 20, 26, 27]. An explanation of these terms was presented by Lawrence L. Wang [27]. The remnants of Serres are the remnants of dental lamina deterioration that function as an initiator of tooth formation, which takes place during the 6th week of gestation. The epithelial remains of Malassez are the residual cells after breakdown of Hertwig’s epithelial root sheath, which is mainly responsible for the formation of the root. A reduced enamel epithelium is the epithelial tissue that circles the crown of the tooth. The remnants of Serres [7, 15] are thought to be the most possible theory of GC deve­lopment in both infants and adults. This is supported by a research done by Moskow and Bloom [24] on embryogenesis of the gingiva. Although GC is an unusual type of a developmental cyst, it is not as rare as stated by seve­ral publications [25]. Its occurrence in children is also not that common compared with adult population [25]. Richman and Johnston [25] demonstrated only 3 cases of GC in children. Karmakar et al. [23] reported a hypothesis on why GCA is derived from an odontogenic form of dental lamina. Based on their writing, a study was conducted on a human fetal head. It was discovered that the epithelial branch connecting the developing tooth to the dental lamina degrades between the 9th and 10th week in utero, leaving epithelial remnants. The epithelial remnants of the dental lamina are today known as glands of Serres. This epithelial stalk subsequently undergoes cystic breakdown, as evidenced by its deterioration even before the dental lamina disintegrates. The presence of micro- cysts can lead to their detachment within the oral cavity during tooth eruption. In some cases, these detached cysts may persist until adulthood and transform into GCA. However, Shear and Pindborg [28] share opposite presumption. They stated that the origin of GCA and lateral periodontal cyst (LPC) may have come from epithelial remains of Malassez, or reduced enamel epithelium. Furthermore, both LPC and GCA can have a glycogen-rich clear cell rest of the dental lamina, but Wysocki et al. [15] could not find any of these in the epithelial remains of Malassez, nor in the reduced enamel epithelium. This finding supports even more the theory that GC arises from the epithelial remains dental lamina. GCA and LPC share a lot of similarities, often leading to the same diagnosis, since their histological morphology, location, and predilection are very similar [2, 7, 15, 22-24].
Very interesting findings were mentioned in [7, 15, 25, 26], suggesting that GCA and LPC are the extra­osseous and intraosseous complement of each other. However, a distinction should be made between GCA and LPC when it comes to the cell origin, where the latter arises from periodontal ligament [25]. World Health Organization also categorize these two cysts separately, in spite of the fact that both are considered developmental odontogenic cysts [25]. Buchner et al. [2] suggested two different origins of how GC develops in adults: odontogenic origin (as explained above) and non- odontogenic, e.g., due to traumatic injury, mechanical trauma, or surgical injury.
Clinically, GC most commonly manifests as a firm, dome-shaped nodule with a smooth texture. This nodule can be either round or oval in shape [4, 5, 7]. The color may vary slightly, from bluish, blue-grey, to yellow-pink. These nodules are usually painless [14], although discomfort and pain has been reported during toothbrushing [3]. Symptoms are limited to the oral cavity, and no general signs were reported. GC may affect deeper layers of the mucosa, and showed radiographic changes in the underlying alveolar bone. Tolson et al. [20] and Cairo et al. [3] both characterized GC as slow-growing lesion, with an absence of symptoms. Gingival swelling may occur, and was noted in the labial aspect of the jaw between lower canine and lateral incisor [3]. Additionally, the gingival swelling can affect the adjacent periodontal pocket, causing bleeding and locally increased PPD. GC presents as a non-inflammatory [14] swelling, fluid- filled nodule, or elevated mass [18] located in the free and/ or attached gingiva or gingival papilla [2, 5], most frequently occurring in the mandibular incisor-canine- premolar region [1-12, 14-21]. Regarding color, this odontogenic cyst can have whitish, bluish, blue-gray, or gray appearance due to mucosa thinning [6], but also a pinkish color as that of healthy gingiva [5, 6]. Its dimensions vary between 0.1 and 1.5 cm [2, 12]. According to Buchner et al. [2], the most common dimensions differ between 0.1 and 0.6 cm in diameter, and concern 82% of cases analyzed. However, in a study by Viveiros et al. [14], GCs diameters with an average value of 5.86 mm were reported. Also, Sato et al. [12] presented a case that measured 2 cm in diameter, and according to Deliverska and Stamatoski [6], lesions > 5 cm can appear. Additionally, in a study done by Chrcanovic and Gomez [4], the average size of GC varied between 0.3 and 0.9 cm, while the maximum size was reported as 2 cm. Most of the lesions presented by these authors were smaller than or 1 cm [2, 3, 6-9, 14, 15, 18-20]. The dia­gnostic process of GC can cause difficulties, as there are several factors influencing the diagnosis. GC is an extra­osseous lesion [4, 5, 7, 20], appearing in the area of vital teeth [5, 7, 8, 13, 19, 20], which usually does not cause extensive bone resorption [3, 5, 6, 12, 19, 20] but saucerization [2, 3, 5-7, 12, 16, 19, 20] of the superficial bone structure, which can be due to the pressure created by the fluid accumulated inside [19] of bigger dimension lesions. However, a case of bone resorption and root exposure by GC has been reported by Kelsey et al. [19]. The most commonly seen differential diagnosis of GC are lateral periodontal cyst (LPC) [3, 4, 6, 8, 9, 13, 14, 19, 22, 24], botryoid odontogenic cyst (BOC) [3, 4, 22], or mucocele [6-8, 14, 19], even though the typical location of mucocele is not the attached gingiva [18]. Both GC and LPC are types of odontogenic cysts, which are most likely to be confused with each other due to same age predilection [7, 9], developmental process [7, 9], and possible radiolucency [7, 14, 18] (GC – 20%, 2 out of 10 cases according to Viveiros et al. [14] study on conventional radiographs). Clinically, both the cysts have comparable anatomic location in the oral cavity [2, 3, 7, 9], morphological appearance, and behavior [7, 9]; how­ever, GC is usually smaller than LPC [4]. Histolo­gically, they originate from the same type of tissue with squamous and cuboidal cell layers [2, 4, 10, 12, 18, 19,], but they cannot be differentiated this way [1, 9, 13]. Two factors which help distinguish GC from LPC are radiological examination [5, 13, 19] and excisional biopsy [2-4, 7, 13, 14, 19]. Radiologically, GC shows no bony and periodontal involvement [2, 20], with rare and diffuse radiolucency [2, 18], but it is usually not visible on X-ray [7, 8]. While LPC is seen on X-ray as a well- demarcated radiolucency [6, 18] due to its intraosseous origin, thus indicating bony and periodontal involvement [2, 7, 20]. To finalize the diagnosis, excisional biopsy [2, 3, 5, 7, 13, 14, 19] should be performed to uncover the bone beneath the lesion, evaluate its condition, and mark the characteristics of bone saucerization [2, 5, 19]. Due to the high-rate of GC misdiagnosis (only 50% of cases are correctly identified [18]), it is crucial to consider GC when diagnosing gum lesions with similar appearances. Fortunately, treatment for adult GC is usually simple. Excisional biopsy with removal of the cyst is the standard approach, rarely resulting in a recurrence [29]. This procedure consist of a simple cysts’ removal with minimal surrounding tissue involvement, followed by microscopic (histopathological) examination to confirm the diagnosis [30]. Although excisional biopsy is the standard treatment for GC, less common methods were used in a small percentage of cases, including curettage (2.7%) and enucleation (0.9%). Patients were followed up for time periods ranging from 1 to 92 months. Only one study reported a case of GCA recurrence that appeared after 7 years from initial cyst removal. However, it is unclear whether this was a true recurrence or a new lesion developing in the same location [31].

Conclusions

Gingival cysts in adults are rare lesions specific to the oral cavity. They typically appear in patients aged between 50 and 60 years. In less than half of cases, the underlying bone is affected. The definitive treatment for these cysts is excisional biopsy, involving removal of the entire cyst. Root exposure, where the tooth root becomes visible, is very rare. If this occurs, an approach combining removal and regenerative techniques might be necessary to address both the bone loss and soft tissue defect remains after removing the cyst. Early detection and treatment mitigate muco-gingival defects, and improve clinical outcomes. Even though gingival cysts are uncommon, it is important to include them in the possible diagnoses when examining gum lesions.

Disclosures

1. Institutional review board statement: Not appicable.
2. Assistance with the article: None.
3. Financial support and sponsorship: None.
4. Conflicts of interest: The authors declare no potential conflicts of interest concerning the research, authorship, and/or publication of this article.

References