Lateral Periodontal Cyst - A diagnostic dilemma: Report of a rare case with CBCT and histological findings

Abstract

Introduction: Lateral Periodontal Cyst (LPC) is considered as a rare developmental odontogenic cyst. It is often diagnosed as an incidental radiographic finding, presenting as a circumscribed round radiolucent area between the roots of vital teeth. LPC usually does not present any clinical features. Differentiating the origin of the lesion from an endodontic or periodontal perspective presents as clinical challenge.

Presentation of case: A female patient presented with an asymptomatic gingival swelling in the lingual aspect of mandibular anterior region. The associated tooth (#34) was endodontically treated 3 years back. A periapical radiograph showed a well-defined round radiolucency on the tooth. Cone beam computed tomography (CBCT) revealed extensive bone destruction. The lesion was surgically excised and histological examination confirmed the diagnosis of LPC. The site healed satisfactorily post-operatively. The case was followed up for a year without any recurrence seen.

Discussion: LPC is a very rare clinical entity, the diagnosis of which requires a detailed case history taking, clinical and radiographic examination are essential to get proper assessment of the pathology. It is said to originate from either the remnants of dental lamina, reduced enamel epithelium or rests of Malassez. LPC presents with a typical histological picture which ensures the confirmatory diagnosis. Surgical enucleation with thorough curettage is the treatment of choice.

Conclusion: By reporting this rare case, we would like to stress to clinicians that there are a wide range of cysts and anatomic structures are present in the canine-premolar region of mandible of which LPC is a rare possibility.

Keywords: CBCT; Case report; Developmental cyst; Endodontically treated tooth; Gingivectomy; Lateral periodontal cyst.

Fig. 1

A] Mirror image of gingival swelling seen in lingual aspect of mandibular canine (#33) and first premolar (#34) area. B] IOPA X ray showing ovoid radiolucency in mesial aspect of #34. C] CBCT image showing the soft tissue shadow of the gingival enlargement in lingual aspect of #34 as well as the extensive bone loss in the lingual cortical bone.

Fig. 2

[A-D]: Histopathological examination of the excised lesion showing showed cystic lumen lined by 2–3 layers of non-keratinizing cuboidal cells resembling REE which were hyperplastic at places. The lining epithelium also showed clear cells, localized thickenings/plaques and mural bulges. The underlying connective stroma is dense collagenous made up of bundles of collagen fibers, fibroblasts, blood vessels and dense infiltration of chronic inflammatory cell infiltrate. The overlying epithelium is parakeratinized stratified squamous in nature and is separated from the lesional tissue by a zone of normal connective tissue stroma.

Fig. 3

A] On excision of lesion, extensive destruction of bone and expansion of cortical bone seen. B] 4 weeks post-operative IOPA xray showing filling of bony lesion. C] 4 weeks post operative clinical photograph showing healing lesion (mirror image) D] 8 weeks post operative clinical photograph showing satisfactory healing (mirror image).