Dermoid cysts represent approximately 34% of developmental cysts in the head and neck region, and they occur mostly at the midline of the floor of the mouth. However, dermoid cysts may also migrate laterally by expansion. The lesion is usually slow growing and painless, presenting as a doughy or rubbery mass that frequently retains pitting after application of pressure. The differential diagnosis for dermoid cysts includes infections, tumors, mucous extravasation phenomena and abnormalities arising during embryonic development.
In this report, we present three cases of unusual oral dermoid cysts. The first case developed on the left floor of the mouth, the second case was in the left submandibular area, and the third case was in the sublingual and submental space. All lesions were removed by the intraoral approach. Histopathologic examination revealed a dermoid cyst. The cysts were lined by orthokeratinized stratified squamous epithelium, with a prominent granular cell layer. The cyst walls were composed of fibrous connective tissue that contained sebaceous glands, sweat glands, and hair follicles.

Ⅰ. INTRODUCTION
 Ⅱ. MATERIALS and METHODS
 Ⅲ. RESULTS
  1. Case Ⅰ
  2. Case Ⅱ
  3. Case Ⅲ
 IV. DISCUSSION
 ACKNOWLEDGMENT
 V. REFERENCES

• Seong-Yong Moon(Department of Oral & Maxillofacial Surgery, School of Dentistry, Chosun University) | 문성용
• Jung-Hoon Yoon(Department of Oral and Maxillofacial Pathology, College of Dentistry, Wonkwang Bone Regeneration Research Institute, Wonkwang University Daejeon Dental Hospital) | 윤정훈 Corresponding Author