MRI features are most consistent with a Gartner duct cyst with no associated urinary system anomalies (both kidneys were normal on ultrasound and not shown).
Gartner duct cysts are typically located above the inferior aspect of the pubic symphysis, within the walls of the vagina. They are often noticed incidentally on ultrasound or MRI; the symptoms are usually due to the mass effect on adjacent structures.
The main differential diagnosis includes: