Postauricular Cyst in a 15-Year-Old Girl

A 15-year-old girl presented to the otorhinolaryngologic department for a right-side postauricular mass. The mass had been present since birth but had slowly grown larger in the previous 2 years. On physical examination, a 2.5 × 1.5-cm, nontender, blue, soft, cystic mass was observed in the right postauricular area. There were no fistular openings around the auricle or in the external auditory canal (EAC), and there were no additional cysts, sinuses, or fistulas at the right neck from the hyoid bone and chin to the EAC. On temporal bone computed tomography, a 2.5 × 1.5-cm, hypodense, oval-shaped cystic mass was revealed at the subcutaneous fat layer superoposterior to the right auricle. On temporal magnetic resonance imaging (MRI), an oval cystic mass was revealed at the same location, with high signal intensity on both T1-weighted and T2-weighted images and low signal intensity on enhanced T1-weighted fat suppression and T2-weighted short T1 inversion recovery images (Figure, A-D). In surgery, the well-demarcated cystic mass was completely excised. Yellowish fluid leaked out of the cyst during excision. On histopathologic examination, the cyst was lined by keratinizing stratified squamous epithelium with hair follicles and sebaceous glands. The cyst contained keratinous debris (Figure, E). There was no recurrence 6 months after surgery.