Image 8 – Diagnosis: Bartholin's gland cyst

• Panel A (axial CT/MRI, bone-window reference) — the bright "wishbone" structure in the midline is the pubic symphysis/ischiopubic rami; the yellow arrow points to a well-defined, rounded, low-attenuation/hypointense lesion just posterolateral to the vaginal introitus.
• Panels B, C, D (T2-weighted and fat-saturated axial MRI sequences at the level of the vulva/lower vagina) — a homogeneous, unilocular, high T2 signal (fluid-filled) rounded lesion is seen in the same posterolateral vulvar location, deep to the labia majora, corresponding to the site marked by the arrow and asterisks. The contralateral side is normal, confirming the finding is unilateral and focal rather than a symmetric normal structure.

• Bartholin (greater vestibular) glands sit bilaterally in the posterolateral aspect of the vaginal introitus/vulva, below the hymenal ring — exactly the level shown in these images.
• On MRI, a Bartholin duct cyst classically appears as a well-circumscribed, unilocular, T2-hyperintense (fluid signal), T1-hypointense cystic lesion with a thin wall and no significant enhancement or septations, exactly matching the round bright lesion in panels B-D.
• This differs from a Gartner duct cyst (anterolateral vaginal wall, higher up along the course of the mesonephric duct) and from a Skene gland cyst (periurethral, near the external urethral meatus) — both of which are more anterior/superior than the location demonstrated here.