The<unk>  is a form of a uterine anomaly or variation where the uterine fundus displays a concave contour towards the uterine cavity. Normally the fundus of the uterus is straight or convex on anterior-posterior imaging but in the<unk>  it dips into the cavity and may form a small septation. The distinction between an<unk>  and a septate uterus is not standardized.
Arcuate uterus
Septate uterus
Retroverted uterus
Uterine didelphys
Vaginal cysts
Peritoneal inclusion cyst
Spermatic cord cyst
Enlarged uterus