Inflammatory Paradental Cyst: A Case Report and Literature Review

INTRODUCTION

Radiolucent lesions of the jaws have been a dilemma for surgeons regarding whether to treat radically or conservatively, especially when they are associated with an impacted tooth. The inflammatory paradental cyst is a rare lesion associated with an impacted tooth, which was first described by Hofrath. Such lesion offers a diagnostic challenge between other lesions like odontogenic keratocyst, dentigerous cyst, and ameloblastoma. Herein, we report a rare case of a large lesion that was diagnosed incidentally on an incisional biopsy, confirmed histopathologically as an inflammatory paradental cyst, and managed successfully surgically.

CASE DESCRIPTION

An 18-year-old female reported to the Department of Oral and Maxillofacial Surgery with a complaint of pain and swelling in the right-lower back-tooth region since 2 months. History revealed occasional pus discharge since 1 month. No contributory history of trauma or caries was elicited. On extraoral examination, a swelling was noted on the right-side mandibular ramus region that was bony hard on palpation. Intraorally, mouth opening was within normal limits, inflamed mucosa was seen over the partially erupted third molar with clear fluid discharge on palpation. Paresthesia was also observed on the right side of the mandible (Fig. 1).

For diagnostic purposes, an orthopantamogram was taken, which revealed a distoangular-impacted right-lower third molar and a large radiolucent lesion (60 mm × 20 mm) with a sclerotic border seen extending from the distal surface of the right-lower second molar to the subcondylar region superiorly and up to inferior alveolar canal inferiorly (Fig. 2). The vitality of the associated and neighboring tooth was confirmed with an electric pulp tester to rule out dental foci.

An aspiration biopsy was done, which showed cream color fluid with blood stains (Fig. 3). Although the initial impression of this lesion gave a provisional diagnosis of odontogenic keratocyst/dentigerous cyst and to rule out the possibilities of other lesions, an incisional biopsy was done (Figs 4 and 5). The histopathological report revealed it to be an inflammatory paradental cyst, which was a rare entity. The treatment plan was surgical removal of the right-lower third molar and enucleation of the cyst as the literature suggests nonradical treatment for the inflammatory paradental cyst.

SURGICAL PROCEDURE

Under general anesthesia, a crevicular incision with anterior releasing from the first molar region was given and extended onto the anterior border of ascending ramus. Subperiosteal flap raised and thinning of cortical plates was observed. Surgical removal of the right-lower third molar was done (Fig. 6) and the cystic lining was seen attached to the distal root of the third molar, which was carefully detached from the mucosa. Gradual enucleation was done extending up to the subcondylar region preserving inferior alveolar vessels (Fig. 7). Hemostasis was achieved and the wound closed primarily using a 3-0 Vicryl suture (Fig. 8).

The histopathological report of the excised specimen (Fig. 9) showed characteristic features of a paradental cyst and confirmed our initial diagnosis (Fig. 10).

Postoperative follow-up shows good bone formation on the radiograph without any evidence of recurrence (Figs 11 and 12).

DISCUSSION

Even though Hofrath was the first to uncover numerous cases of comparable jaw cysts in 1930,¹ it was Main who identified cysts distal to the third mandibular molar with pericoronitis in 1970 and coined the name “inflammatory collateral cyst”. Craig, on the other hand, coined the term “paradental cyst”.² However, Vedtofte and Praetorius in 1989 proposed the term “inflammatory paradental cyst”³ which was included in WHO classification for the first time in 1992, and presently it comes under the Inflammatory Collateral Cyst in 2017 WHO classification of odontogenic cysts and tumors.⁴

Incidence is rare representing only 0.9–4.7% of all odontogenic cysts. It usually occurs in patients under the age of 35 years and has a slight male predilection with a 1:0.4 ratio in accordance with the literature.⁵ Our patient falls under the lower limit of the reported age group.

Etiopathogenesis of this lesion is filled with debates and controversies – Ackermann believed the origin is from crevicular epithelium as there was continuity between cyst lining and crevicular epithelium² whereas Main thought that the proliferation of cell rests of Malassez following gingival extension as a result of the pericoronitis⁶ and according to Craig, reduced enamel epithelium results in this lesion.⁷

The mandibular area is the most common location, often on the distal aspect of a fully or partially erupted molar. Literature reveals the associated tooth to be vital and reacts normally to vitality testing, which was also observed in our case. It is usually asymptomatic unless the lesion reaches a large size with common symptoms of pericoronitis, which include pain and suppuration.⁸ Extraoral swelling is noted only when cortical expansion occurs and involves the ramus. Supporting the same, in our case, extraoral asymmetrical appearance and pericoronal symptoms were noted.

Intraoral periapical radiographs commonly used to diagnose the impacted third molar may not be sufficient if the lesion has enlarged to a considerable size. Orthopantamogram offers a crucial role in the early detection and diagnosis of such large lesions. Literature suggests that lamina dura is intact and continuous around the root, but this was not seen in our case, maybe because the lesion extended to a large size destroying extensive bone. Colgan’s sign, which indicates the preservation of the distal follicular space in a radiograph, is a useful diagnostic feature to distinguish a paradental cyst from other similar cysts.⁹ With modern technology, the gold standard would be cone-beam computed tomography (CBCT) or computed tomography (CT), which will give a clear-cut diagnosis of involvement of bone in all directions. In a review of the literature, the maximum size of the paradental cyst to be recorded is around 20–30 mm in diameter, whereas we encountered a large ovoid radiolucent lesion measuring almost twice the size (60 mm) in diameter, making it a rare entity.

Histopathological diagnosis is usually made with the presence of hyperplastic, nonkeratinized, stratified squamous epithelium with arcade fashion surrounded by fibrous connective tissue capsule invaded by a chronic inflammatory infiltration.

The differential diagnosis consists of a group of lesions varying from benign to malignant ones like radicular cyst, odontogenic keratocyst, dentigerous cyst, and unicystic ameloblastoma. A positive electric pulp test is a diagnostic criterion for a paradental cyst and hence can differentiate it from a lateral radicular cyst. Colgan’s sign distinguishes paradental cysts from dentigerous cysts because it indicates that most of the follicle is not involved in the process of cyst development. Odontogenic keratocyst is differentiated by growth in an anteroposterior direction with minimal or without cortical expansion. Unicystic ameloblastoma presents as a pericoronal radiolucency with knife-edge type of resorption of adjacent tooth roots and displacement of teeth. However, only a histopathological examination through an incisional biopsy can confirm and differentiate an inflammatory paradental cyst from other lesions. Past research shows that if the tooth is a first or second molar, the best therapy is the enucleation of the cyst without extraction of the tooth, however, surgical removal of the tooth and the paradental cyst is the best course of action when it is the third molar.¹

We advocated the same treatment protocol and successfully managed the patient with good results. The role of adjuvant therapies like chemical cauterization and cryotherapy is not yet described in the literature.

In cases treated with enucleation of the cyst without extraction of the teeth, long-term follow-up is required to check the vitality of the associated tooth. There is some evidence in the literature indicating the self-limiting potential of the paradental cyst because large dimensions have not been reported so far but we contradict this statement as our lesion has progressed to a large size.

We also observed a 1-year follow-up and advise a much longer follow-up for such lesions for early intervention in case of any recurrence.

Inflammatory paradental cysts though benign can be aggressive, therefore, the authors advocate an early treatment. It is also always advisable to do an incisional biopsy to differentiate it from other potentially malignant lesions like ameloblastoma to prevent a radical treatment.

PATIENT CONSENT

A written consent form was obtained from the patient.

ORCID

Nikhil M Kurien https://orcid.org/0000-0002-9369-3349

Mathew Tharakan https://orcid.org/0000-0003-1793-9439

Adersh GA https://orcid.org/0000-0002-1282-0239

Mathew Joseph Thuruthel https://orcid.org/0000-0003-0402-3624

Varun B Raghavan https://orcid.org/0000-0002-1538-2860

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