Urogenital sinus origin of mucinous and ciliated cysts of the vulva.

The origin of mucinous and ciliated cells in the vulva and the pathogenesis of cysts lined by these epithelia were investigated. Small mucinous glands numbering from one to more than a hundred were encountered in 9 of 19 vulvas (53%) that were consecutively examined at autopsy. Eleven other cysts were encountered clinically. Six were lined by mucinous epithelium, three by pseudostratified cells with cilia plus small foci of mucinous epithelium, and two by ciliated epithelium only. Four of the cysts with ciliated epithelium were otherwise typical Bartholin's gland cysts. It is concluded that glands lined by either mucinous or ciliated epithelia are normal constituents of the vulvar vestibule, are derived from urogenital sinus, and develop into cysts when the neck leading to the vulvar surface becomes inflamed and obstructed.