Post-auricular dermoid cyst- uncommon lesion at an uncommon site

Dermoid cyst in the post auricular region is a rare occurrence, with only a handful of cases described in the literature. It is an uncommon benign midline cyst which arises in the sub-cutaneous plane, but deeper extension into bone to intra-cranial and intra-calvarial has been reported. The usual presentation is asymptomatic, but it can present as a swelling gradually progressing in size, pain following secondary infection or rupture of the cyst. Malignant transformation of the cyst is exceedingly rare but has been reported. Here we discuss a case of a middle aged female with left dermoid cyst in the mastoid region which was excised surgically and showed no recurrence in the 6 month post-operative period. It is imperative to mention that the removal of the cyst with its wall in entirety is required to prevent recurrence. The final diagnosis is made based on the histo-pathological examination of the excised specimen.