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.

This report describes a rare case of primary rectal mature teratoma in a 56-year-old woman. She was referred to the outpatient clinic with a large pedunculated rectal mass, which was found during a regular health check-up. Polypectomy was performed and microscopic findings showed various structures derived from all three germ cell layers. Epidermis, hair follicles, sebaceous glands, eccrine glands, and apocrine sweat glands, with some scattered melanophages and lymphocytes were present as ectodermal derivatives. Smooth muscle fibers, blood vessels, and fibrous and adipose tissues were found as mesodermal derivatives. In addition, thyroid follicles, mucinous glands, and bronchial respiratory epithelium with peribronchial glands were detected as endodermal derivatives. She is healthy and has shown no evidence of recurrence or distant metastasis for 25 months post-surgical resection. Primary rectal teratomas are generally benign and primarily affect women. Therefore, minimally invasive surgical procedures, such as endoscopic polypectomy for a pedunculated polyp and segmentectomy for a larger mass, are satisfactory in most cases. Induction of primary rectal teratomas has been suggested to occur mainly by errors in a single germ cell after the end of meiosis I; in addition, it has also been suggested that the difference in gender incidence may be associated with differences in sex chromosomes between males and females rather than with anatomical proximity between ovary and rectum.