Abstract
Objectives: The purpose of this report is to describe an example of epidermal inclusion cysts (EIKs) of the parapharyngeal space (PPS) as an unusual complication of ear surgery.
Methods: A 46-year-old man presented with a 6-month history of a slow-growing mass in the right preauricular region overlying the parotid gland. On physical examination, a 3 × 4-cm soft tissue mass was noted. MRI of head and neck demonstrated that there were soft tissue masses in the PPS. He had a history of chronic otitis media and 5 years previously had undergone a tympanomastoid (TM) surgery. The mass was totally excised via a transparotid approach. Histologic examination revealed a cystic cavity containing laminated keratin strands and lined by keratinized stratified squamoz epithelium. This confirmed the diagnosis of an EIK.
Results: EIKs are rare tumors and have a predilection for highly traumatized sites of the body. These cysts have also been described in various other regions and in tissues deeper than the dermis. Epidermal cysts may be congenital or acquired in origin, and the distinction between the two is determined mainly by the history of the patient. Acquired cysts are most commonly of traumatic origin and result from an implantation of an epidermal fragment. Symptoms may vary depending on the location of the tumor and the pressure on the surrounding structures. A review of the literature reveals that the PPS is an unusual site for the EIK.
Conclusion: EIKs must be considered in the differential diagnosis of parapharyngeal space growths, especially in those cases with histories of previous TM surgery on the tumor site.