Eccrine Poroma on the Postauricular Area: A Rare Presentation
A 55-year-old Korean male presented with a mass on the right postauricular area for the last 10 years. The mass had gradually increased in size, and was not associated with pain or discharge. The examination revealed a solitary, 1×1 cm, protruding, dome-shaped, glistening, skin-colored-to-black mass (). Epidermal cyst or trichofolliculoma was considered in differential diagnosis. There was no previous history of trauma to the area. Histopathologic findings showed a tumor in the epidermis comprised of broad anastomosing bands with a sharp demarcation from the stroma (). Narrow ductal lumina were found within the tumor. They were lined by a single row of the luminal cells covered by an eosinophilic lining (). The tumor cells were smaller than epidermal keratinocytes and showed a uniform cuboidal appearance with a deeply-basophilic, round nucleus. They were connected by intercellular bridges (). The diagnosis was confirmed by histopathologic findings as an eccrine poroma. The tumor was excised and no recurrence was noted during the follow-up period of 5 months.