Benign Ovarian Cysts

An ovarian cyst is a fluid-filled, blood-filled, or partly solid adnexal structure. “Benign-appearing” describes its clinical and ultrasound risk pattern; it does not establish histology. The useful distinction is between a functional cyst, which develops from the normal ovarian cycle and usually resolves, and a pathological mass, which persists or has features suggesting endometriosis, neoplasia, infection, or another structural process. Clinical reasoning rests on four linked questions: Is the patient stable? Does the symptom pattern suggest torsion, rupture, or infection? Does ultrasound show a simple benign morphology or suspicious architecture? Does the lesion resolve within the expected interval? Menopausal status changes the prior probability of malignancy and therefore changes the threshold for investigation and referral. In a premenopausal patient, a follicle measuring up to 3 cm and a corpus luteum measuring up to 3 cm are normal physiologic findings and do not require follow-up. Most functional cysts disappear without intervention within two or three menstrual cycles. A persistent lesion deserves reassessment because persistence makes a purely physiologic explanation less likely.