A Case of Cutaneous Ciliated Cyst with Immunohistochemical Evidence for Müllerian Origin

Cutaneous ciliated cysts (CCC) are rare developmental lesions that are generally located on the lower limbs of young females. As their lining closely resemble Fallopian tube epithelium, they are regarded as Müllerian heterotopias. Their estrogen receptor (ER) and progesterone receptor (PR) expressions also support this theory. Here we report an other example of CCC located on the left buttock of a 12-year-old girl that occurred as a small subcutaneous mass shortly after puberty. The cyst was lined by pseudostratified ciliated epithelium devoid of goblet cells and had a fibrous wall. There were no muscle bundles in the wall. The epithelium expressed EMA, ER and PR, but not CEA immunohistochemically.