The Cutaneous Ciliated Cyst in Young Male: The Possibility of Ciliated Cutaneous Eccrine Cyst

Cutaneous ciliated cyst was described as a painless cyst occurring on the lower limbs of women between the ages of 15 and 30 years. The cysts are typically lined by ciliated cuboidal to columnar epithelium with pseudostratified areas and focal squamous metaplasia is occasionally present. Immunohistochemical studies have demonstrated that the cysts are PR and ER positive, similar to the epithelia of the fallopian tubes. However, outliers of cutaneous ciliated cysts, including those in male patients and in unexpected locations such as the scalp, finger, and scapular area, have been reported. Thus, some hypotheses have been proposed including the Mullerian heterotopias, ciliated metaplasia of eccrine sweat glands, and embryonic remnants of the cloacal membrane. We report a rare case of cutaneous ciliated cyst on the left shoulder of a 7-year-old boy and this is the eighth case of cutaneous ciliated cyst in male patients. Moreover, through reviewing the articles, we try to propose the classification of the cutaneous ciliated cysts into the cutaneous Mullerian cysts and the ciliated cutaneous eccrine cysts.