Benign Ovarian Cysts: The presence of clear, septated cysts with stable size over time and low CA125 levels suggests a benign nature. The description of "follicular changes" in the ovaries further supports this, as it is a common finding in postmenopausal women.

Simple Ovarian Cysts: These are common in postmenopausal women and can be multiple. The clear and septated appearance, along with stable size and low CA125, aligns with simple cysts.
Hemorrhagic Cysts: Although less likely given the clear description, hemorrhagic cysts could present with septations if there are areas of clotting. However, they typically resolve over time, and the stability of the original cyst makes this less likely.
Serous Cystadenomas: These are benign ovarian tumors that can be septated and filled with clear fluid. They are common in postmenopausal women and could explain the findings.

Ovarian Cancer: Although the low CA125 levels and the clear, septated nature of the cysts are reassuring, ovarian cancer cannot be entirely ruled out without further investigation. The presence of multiple cysts and the postmenopausal status of the patient necessitate careful consideration of this diagnosis.
Borderline Ovarian Tumors: These are tumors of intermediate malignant potential. They can present similarly to benign cysts but require histological examination for diagnosis.

Mucinous Cystadenomas: These are benign ovarian tumors that can be large and septated. They are less common than serous cystadenomas and typically contain mucinous fluid.
Dermoid Cysts: Although more common in younger women, dermoid cysts can occur in postmenopausal women. They are usually filled with sebaceous material and can contain hair, teeth, or bone, which might not be evident on initial imaging.
Lymphangiomas or Other Rare Ovarian Tumors: These are extremely rare and would be unusual in a postmenopausal woman. They could potentially present as septated cysts but are much less likely than the other diagnoses listed.