Lateral dermoid cyst

Abstract

Columbia University’s Salivary Gland Center (New York, NY) serves as a referral base for metropolitan New York City patients with salivary gland disease and/or salivary dysfunction. Since its establishment, the Center has seen approximately 6,000 patients. Surprisingly, a great many of the referred patients do not have a salivary gland problem. Recently, such a patient was referred with a significant circumscribed swelling in the submandibular area and whose origin was thought to be the submandibular salivary gland (SMSG). A clinical diagnosis of a benign extraglandular cyst was made. It was only after its surgical removal that it was identified as a dermoid cyst (DC). This uncommon pathologic entity in a most uncommon area is the basis of our report. The DC and its epidermoid variant that arise in the head and neck area are believed to result from congenitally included ectoderm that has been trapped during the bilateral embryologic fusion of the mandibular and hyoid, respectively first and second branchial arches. The congenital DC has been classified into 3 categories. The epidermoid cyst is an epithelially lined cavity with a capsule that contains no skin appendages such as hair, hair follicles and sweat, and sebaceous glands. The second category, the DC, differs only in that it contains skin appendages. The teratoid cyst also contains skin appendages, but in addition connective tissue derivatives (eg, bone, muscle) are present. The teratoid variety of the oral DC is extremely rare and its existence is doubtful. The delineation of a DC from an epidermoid cyst has no clinical significance and is dependent only on gross and microscopic findings. A noncongenital entity similar to the DC also can develop from the traumatic inclusion of skin into the underlying tissue. Here, the epidermal cells can form an epithelially lined cyst. Dermal appendages may or may not be present. New and Erich’s exhaustive review of 1,495 cases of DC indicated that only 103 (6.9%) occurred in the head and neck area. The orbital area, because of the complex fusion lines that are present, is where most cervicofacial dermoids were found. The oral region, particularly the midline of the mouth floor, was the next most frequent location for the head and neck DC. Twenty-four cases were reported in the oral region, while only 7 were located in the submandibular area. Although rare, other investigators also have reported its occurrence in the submandibular/cervical area. Because of its rarity, no determination of a statistically significant incidence can be made. The origin of the lateral DC is somewhat puzzling. Generally, it is thought to originate in the midline of the oral cavity, above the mylohyoid, and then shift its Received from the Salivary Gland Center, Columbia University