Mandibular buccal bifurcation cyst: A rare pediatric odontogenic lesion with radiographic, histopathological, and clinical insights

INTRODUCTION

The buccal bifurcation cyst (BBC) is an uncommon inflammatory odontogenic cyst that predominantly arises on the buccal side of the first or second mandibular molars in pediatric patients.^[1] Initially described by Stoneman and Worth 36 years ago, it was termed the “mandibular infected buccal cyst.”^[2] Over the years, this lesion has been referred to by multiple names, such as juvenile paradental cyst,^[3] mandibular BBC (MBBC),^[4] inflammatory lateral periodontal cyst, and inflammatory paradental cyst.^[5] According to the World Health Organization (WHO), both the MBBC and paradental cysts are now grouped under the category of inflammatory collateral cysts.^[1] These cysts are believed to originate from inflammation in the soft tissues surrounding erupting teeth and are considered to have a similar pathogenesis. While paradental cysts are most often linked to the mandibular third molars, MBBC is usually found involving the buccal region of the first and second mandibular molars.^[6] Clinically, BBC may manifest as buccal swelling, delayed or incomplete eruption of teeth, and the formation of deep periodontal pockets. In some instances, additional symptoms such as pain, localized infection, or purulent drainage may be observed.^[7] This article presents a rare occurrence of an MBBC in a child.

CASE REPORT

A 14-year-old male patient presented with a gradual onset, progressive swelling in the lower right back tooth region, around the second molar, which had been present for 1 month. The swelling was dome-shaped with buccal expansion, firm in consistency, tender on palpation, and associated with mild pain but no pus discharge. The patient had a history of recurrent pericoronitis related to tooth 47. Clinical examination revealed no carious lesions on teeth 46 and 47. Vitality tests revealed that the tooth was vital, showing a normal response to electric stimuli. Radiographic findings showed a well-defined U-shaped radiolucency around tooth 47 along with buccal tilting. Expansion and thinning of buccal cortex were noted [Figure 1a-c]. A provisional diagnosis of unicystic ameloblastoma was made based on the clinical and radiographic presentation. The patient was referred to the department of Oral surgery, Government Dental College, Srinagar, for treatment. After obtaining informed consent from the parents of the patient, the lesion was surgically managed through enucleation, along with the extraction of the involved tooth under local anesthesia. The specimen was sent to the Department of Oral Pathology, Government Dental College, Srinagar, for histopathological examination. The specimen consisted of four tissue fragments along with an extracted tooth with a tissue fragment firmly attached to it. The tissue fragments were brownish, firm, and measuring 3 × 2 cm in aggregate [Figure 1d]. Histopathological examination revealed a cystic cavity lined by non-keratinized stratified squamous epithelium, exhibiting mild-to-moderate hyperplasia with evidence of an arcading pattern. The cyst wall was composed of fibrous connective tissue, containing varying amounts of inflammatory cells, predominantly lymphocytes and plasma cells, and occasionally, foamy macrophages [Figure 1e and f]. Since the involved tooth was vital and the lesion was radiographically observed on the buccal aspect of the tooth, along with tilting, the final diagnosis of an MBBC was made. The patient was reviewed after 2 weeks and was asymptomatic, in good general condition, with radiographic evidence of satisfactory healing [Figure 2a and b].

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Figure 1:

(a) OPG showing a well-defined, unilocular radiolucency in the apical aspect of mandibular second molar [denoted by orange colour arrow]. (b and c) CT scan showing a well-defined, unilocular cystic lesion located on the buccal aspect of the mandibular second molar with mild buccal tilting of the molar [denoted by orange colour arrow]. (d) Gross appearance of the excised specimen along with an associated tooth. (e and f) Histopathological photomicrograph shows the cystic lining composed of non-keratinized stratified squamous epithelium with evidence of hyperplasia and arcading pattern [denoted by black arrow] [4× and 10×]. The cyst wall contains a significant chronic inflammatory infiltrate, predominantly consisting of lymphocytes and plasma cells, within the fibrous connective tissue. OPG: Orthopantomogram, CT: Computed tomography.

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Figure 2:

(a and b) Post-operative radiograph at 2 weeks follow up demonstrating significant healing at lesion site [denoted by orange color arrows].

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DISCUSSION

The BBC is an uncommon inflammatory odontogenic cyst that predominantly affects the buccal region of the mandibular first or second molars in children. It most frequently involves the buccal surface of the mandibular first molar and accounts for <1% of all odontogenic cysts. Although rare in adults, occurrences in the maxilla are even more uncommon. While BBC typically presents unilaterally, bilateral involvement has been reported.^[8] The exact etiology remains unclear. One hypothesis suggests that inflammation may arise from a deep periodontal pocket associated with a tilted molar.

Another theory attributes its development to aberrant tooth eruption triggering inflammation, which subsequently leads to epithelial proliferation and cyst formation. In addition, enamel extensions from the cementoenamel junction toward the furcation area, encased by reduced enamel epithelium, are also believed to play a role.^[9] According to the WHO, the MBBC is classified as an odontogenic cyst. It typically appears adjacent to a vital tooth, near the buccal cervical margin along the root surface, and results from an inflammatory response within a periodontal pocket.^[10]

Clinical presentation of the BBC typically includes the following features:^[11]

• Most commonly affects children between 6 and 11 years of age

• Frequently involves the mandibular first molar, and less commonly the second molar

• The involved tooth usually displays abnormal eruption with a buccally tilted crown

• Pulp vitality is generally preserved

• A deep periodontal pocket is often noted on the buccal aspect

• Buccal swelling may be present but is not always observed

• Patients may report discomfort or tenderness

• Secondary infection may or may not be present.

Radiographic characteristics of BBC’s include:^[11]

• A distinct, radiopaque, concave margin on the lower aspect, giving rise to a U-shaped radiolucency overlapping the molar roots

• The periodontal ligament space and lamina dura are usually preserved

• Due to buccal tilting, the lingual cusps may appear more prominent on radiographs

• The tooth roots are often displaced toward the lingual cortical plate

• The inferior border of the mandible remains intact

• A periosteal reaction may be evident along the buccal cortex

• Signs of buccal cortical expansion and thinning may accompany soft tissue swelling

• Neighboring unerupted teeth might be displaced from their normal positions.

Histopathology of the BBC reveals a lining of non-keratinized stratified squamous epithelium. The cyst wall exhibits a dense chronic inflammatory infiltrate, predominantly consisting of lymphocytes and plasma cells within the surrounding connective tissue.^[12]

Diagnosis should rely on a comprehensive evaluation, incorporating clinical signs, radiographic findings, and histopathological features. The differential diagnosis includes various odontogenic cysts such as lateral radicular cysts, dentigerous cysts, and paradental cysts. A distinguishing feature of BBC is its occurrence in association with a vital mandibular first or second molar, in contrast to radicular cysts, which are typically associated with non-vital teeth.^[13,14] The detailed differentiating features of the lesion from other similar odontogenic pathologies are summarized in Table 1.

Treatment approaches for BBCs have varied. In some cases, conservative management with observation has been attempted, as spontaneous partial or complete resolution has been reported. However, many cases eventually require surgical treatment. Enucleation is the most commonly adopted intervention, either with or without extraction of the involved tooth.^[7]

Ruddocks et al. presented a case series involving ten patients diagnosed with BBC. The average age was 9 years, with a slight male predominance (60%). All cysts were located in the mandible, and bilateral lesions were seen in three cases (30%).^[15]

In a prospective study by Pompura et al., outcomes of BBC treatment were assessed across 44 sites over a 3-year period. The study involved 32 children aged between 5.5 and 11 years (mean age: 7.5 years). All lesions were treated by surgical enucleation without tooth extraction. Follow-up evaluations over 2.5–3 years confirmed complete radiographic healing with no recurrences.^[16]

CONCLUSION

BBC is a rare yet important odontogenic lesion primarily affecting the mandibular first or second molars in pediatric patients. Timely diagnosis through clinical, radiological, and histological correlation is essential to manage the lesion effectively, preserve the tooth, and prevent complications such as infection or bone damage. Surgical enucleation remains a reliable and effective treatment, with an excellent prognosis and minimal risk of recurrence. Continued follow-up is recommended to ensure complete healing and long-term stability.