An endometrial tissue treatment device includes an elongate positioning member and an energy applicator coupled to a distal end of the positioning member, the energy applicator including a tissue contacting member and an expandable-collapsible support structure underlying the tissue contacting member, the expandable-collapsible support structure comprising a substantially non-compliant elongate balloon disposed within the tissue contacting member that, when inflated, has a length oriented substantially transverse to the positioning member, including a first closed end that positions a corresponding first corner portion of the tissue contacting member in a first cornu of a uterine cavity, and a second closed end that positions a corresponding second corner portion of the tissue contacting member in a second cornu of a uterine cavity, with a lengthwise portion of the balloon positioning a distal facing portion of the tissue contacting member for contacting a fundal wall of a uterus.
