Epidermoid cyst arising in the mandibular ramus: A case report

Fuka Homma,Hideki Kizu,Seiji Asoda,Shin Usuda,Takeshi Karube,Tomoki Endo

doi:10.5348/101271z01fh2021cr

Abstract

Introduction: Dermoid and epidermoid cysts are developmental lesions derived from the ectoderm. In acquired elements, trauma and inflammation are hypothesized mechanisms of onset. In the oral region, these cysts mainly develop in the soft tissues such as floor of the mouth, moreover, it is relatively rare in the mandible. Among them, it is extremely rare in the ramus. Case Report: A 48-year-old woman visited dental clinic because of occlusal pain of the left wisdom tooth. The panoramic X-ray film showed an oval-shaped radiolucent area in the left mandibular ramus. Computed tomography revealed radiolucent area in the left mandibular ramus, moreover, there was no bone destruction. Magnetic resonance imaging revealed a lesion measuring 18×17×21 mm in size with mixed moderate and high signal intensity on fat-suppressed T2-weighted imaging in the left mandibular ramus. Gadolinium contrast-enhanced T1-weighted imaging showed no clear enhancement. On the basis of imaging findings, cystic lesion was diagnosed. We performed cystectomy and extraction of the lower wisdom teeth under general anesthesia. Histopathologic examination of the resected specimen revealed the unilocular cyst lined keratinized squamous epithelium. There were no adnexal skin structures such as sweat grand, sebaceous glands, and hair follicles. In addition, the lesions were not associated with teeth and were found only in the mandibular ramus. From these results, it was finally diagnosed as the epidermoid cyst. Three years and six months have passed, but there is no recurrence and a radiolucent area in the panoramic X-ray film shows increased radiopaque. Computed tomography revealed that the defect of the bone is reduced. The postoperative course was uneventful. Conclusion: There is a large amount of literature on jaw diseases; however, we may still come across unique and unclear cases. Clinical examinations, conventional radiography, and surgical experience are not sufficient for the diagnosis of all pathologies. Our case is very rare and is a unique case in the relevant literature because the lesion was limited to the mandibular ramus above the mandibular foramen and was not associated with teeth.

Highlights

INTRODUCTIONDermoid and epidermoid cysts are developmental lesions derived from the ectoderm. Trauma and inflammation are hypothesized mechanisms involved in the onset in acquired cases
Our case is very rare and is a unique case in the relevant literature because the lesion was limited to the mandibular ramus above the mandibular foramen and was not associated with teeth
Dermoid and epidermoid cysts are developmental lesions derived from the ectoderm

Summary

INTRODUCTION

Dermoid and epidermoid cysts are developmental lesions derived from the ectoderm. Trauma and inflammation are hypothesized mechanisms involved in the onset in acquired cases. A panoramic X-ray showed an ovalshaped radiolucent area in the left mandibular ramus. She presented to our department for careful examination. No swelling or induration was observed inside the mandibular ramus, there was no difference between the two sides and the mucosa was a normal color Her medical history included hyperlipidemia, iron-deficiency anemia, and diabetes. A panoramic X-ray revealed an almost circular and well-defined translucent image in the left mandibular ramus (Figure 1). Three years and six months have passed since the operation, panoramic X-ray and CT showed increased radiopacity and bone regrowth, and the postoperative course has been uneventful without recurrence (Figures 5 and 6)

DISCUSSION

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CONCLUSION