Ganer duct cyst is the remnant of the following embryological structure:

Ganer duct cysts are uncommon vaginal cysts develop from remnants of the mesonephric (Wolffian) ducts. They are typically asymptomatic and are usually found within the lateral vaginal wall. Symptoms may include dyspareunia, vaginal pain, and difficulty inseing tampons or other vaginal devices. Examination reveals a tense cyst that is palpable or seen to bulge beneath the lateral vaginal wall. Marsupialization or excision may be appropriate for symptomatic Ganer duct cysts.Ref: Hoffman B.L., Schorge J.O., Schaffer J.I., Halvorson L.M., Bradshaw K.D., Cunningham F.G., Calver L.E. (2012). Chapter 4. Benign Disorders of the Lower Reproductive Tract. In B.L. Hoffman, J.O. Schorge, J.I. Schaffer, L.M. Halvorson, K.D. Bradshaw, F.G. Cunningham, L.E. Calver (Eds), Williams Gynecology, 2e.