Discussion: Dermoid tumors of the head and neck account for nearly 7% of all dermoids in the body.[1] The most common location for germ cell tumors and dermoids in general is the gonads. The superior mediastinum is the second most common site of origin. The head and neck is the third most frequently involved. Dermoid cysts of the head and neck are predominately in the orbit, oral cavity and nasal region. Together these account for over 80% of head and neck dermoids. Dermoids of the floor of the mouth and submandibular space account for approximately 25% of all head and neck dermoids. When found in the oral cavity dermoid cysts are usually in the anterior portion of the floor of the mouth. As such, dermoids of the floor of the mouth account for approximately 1.5% of all dermoids. Nearly all are acquired implantation cysts or congenital rests. Sublingual dermoids as in the case presented here (Fig. 3) elevate the tongue and simulate a ranula often interfering with swallowing. Sublingual dermoids may grow to large enough size to present as pedunculated masses below the mandible. The term dermoid cyst is frequently used as a synonym for benign cystic teratoma and the same name is applied to unrelated sequestration cysts which makes the separation of these two types of lesions difficult.[2] True teratomas of the head and neck arise from embryonic tissue about the primitive streak and nodocord after escaping the external governing influences. Pathologically, dermoid cysts are epithelial lined cavities with variable numbers of skin appendages including hair, hair follicles, sebaceous and sweat glands. The lining ranges from simple stratified epithelium to ciliated respiratory epithelium. Different epithelium may exist in the same cyst. All three types may contain a cheesy material in their cavities. The epidermoid form of teratoma or benign cyst is most common, the dermoid is next in frequency, and the teratoid cyst or teratoma is considered rare in the head and neck.[3].
References:
1. Batsakis JG. Tumors of the Head and Neck. Second edition. John G. Batsakis.
Williams and Wilkins, Baltimore, 1984, pp 226-239.
2. Govepp DR. Sebaceous neoplasms of salivary gland origin. Pathol Ana 1983;18:71-83.
3. Cox CA, Nguyen DL, Medina J. Dermoid cyst presenting as a cold thyroid nodule.
Clin Nuc Med 1996;21:395-402.
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