Cystic Vestibular Gland - Small.
The duct of the right vestibular gland (Bartholin gland) has become occluded, leading to accumulation and distention. Vestibular glands are the homologues of the bulbo-urethral glands in the male. Slight enlargement goes unnoticed. If distension becomes large enough, the bulging mass will part the lips of the vulva and resemble a beginning prolapse of the vagina.
Roberts SJ (1973)