Merck Manual

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Benign Ovarian Masses


Charlie Kilpatrick

, MD, MEd, Baylor College of Medicine

Reviewed/Revised Feb 2023

Benign ovarian masses include functional cysts (eg, corpus luteum cysts) and neoplasms (eg, benign teratomas). Most are asymptomatic; some cause pelvic pain. Evaluation includes pelvic examination, transvaginal ultrasonography, and sometimes measurement of tumor markers. Treatment varies depending on the type of mass; surgery with cystectomy or oophorectomy is done if the mass is symptomatic or cancer is suspected.

Ovarian cysts or other ovarian masses are a common gynecologic issue. Functional cysts, which develop as part of the menstrual cycle, are common and usually resolve without treatment. Masses that are symptomatic or do not resolve may need to be removed surgically to be treated and checked for ovarian cancer.

Functional ovarian cysts

There are 2 types of functional cysts:

  • Follicular cysts: These cysts develop from graafian follicles (fluid-filled sacs that contain ova and are located in the ovaries).

  • Corpus luteum cysts: These cysts develop from the corpus luteum (which forms from the dominant follicle after ovulation). They may hemorrhage into the cyst cavity, distending the ovarian capsule or rupturing into the peritoneum.

Most functional cysts are < 1.5 cm in diameter; few exceed 5 cm. Functional cysts usually resolve spontaneously over days to weeks.

Polycystic ovary syndrome Polycystic Ovary Syndrome (PCOS) Polycystic ovary syndrome is a clinical syndrome typically characterized by anovulation or oligo-ovulation, signs of androgen excess (eg, hirsutism, acne), and multiple ovarian cysts in the... read more Polycystic Ovary Syndrome (PCOS) is usually defined as a clinical syndrome, not by the presence of ovarian cysts. But ovaries typically contain many 2- to 6-mm follicular cysts and sometimes contain larger cysts that contain atretic cells.

Benign ovarian tumors

Benign ovarian tumors usually grow slowly and rarely become malignant. They include the following:

  • Benign (mature) teratomas: These tumors are germ cell tumors; they are also called dermoid cysts because although derived from all 3 germ cell layers, they consist mainly of ectodermal tissue.

  • Fibromas: These slow-growing connective tissue tumors are usually < 7 cm in diameter.

  • Cystadenomas: These tumors are most commonly serous or mucinous.

Symptoms and Signs of Benign Ovarian Masses

Most functional cysts and benign tumors are asymptomatic, but some cause intermittent dull or sharp pelvic pain or, infrequently, deep dyspareunia.

Hemorrhagic corpus luteum cysts may cause pain or signs of peritonitis, particularly when they rupture. Occasionally, severe abdominal pain results from adnexal torsion Adnexal Torsion Adnexal torsion is twisting of the ovary and sometimes the fallopian tube, interrupting the arterial supply and causing ischemia. Symptoms include severe pelvic pain, often with nausea and vomiting... read more of a cyst or mass, usually > 4 cm.

Rarely, ascites and pleural effusion accompany ovarian fibromas;this triad of findings is called Meigs syndrome.

Diagnosis of Benign Ovarian Masses

  • Transvaginal ultrasonography

  • Sometimes tests for tumor markers

Masses are usually detected incidentally during pelvic examination or imaging but may be suggested by symptoms and signs.

A pregnancy test is done to exclude ectopic pregnancy or threatened abortion in a patient with pelvic pain or abnormal uterine bleeding.

Transvaginal ultrasonography is usually the first-line test to confirm the diagnosis.

Masses that have radiographic characteristics of cancer (eg, mixed cystic and solid components, surface excrescences, multilocular appearance, thick septations, irregular shape) or that are accompanied by ascites require consultation with a specialist and excision.

Tests for tumor markers are done if ovarian cancer Diagnosis Ovarian cancer is often fatal because it is usually advanced when diagnosed. The most common histology—high-grade serous epithelial ovarian cancer—is considered as a single clinical entity along... read more is suspected. CA 125 is usually measured in postmenopausal women with an ovarian mass, but its use in premenopausal women requires clinical judgment. This and other tumor markers are not reliable for diagnosis because they lack adequate sensitivity, specificity, and predictive values. For example, tumor marker values may be falsely elevated in women who have endometriosis Endometriosis In endometriosis, functioning endometrial cells are implanted in the pelvis outside the uterine cavity. Symptoms depend on location of the implants. The classic triad of symptoms is dysmenorrhea... read more , uterine fibroids Uterine Fibroids Uterine fibroids (leiomyomas) are benign smooth muscle tumors of the uterus. Fibroids frequently cause abnormal uterine bleeding and pelvic pressure and sometimes urinary or intestinal symptoms... read more Uterine Fibroids , peritonitis, cholecystitis Acute Cholecystitis Acute cholecystitis is inflammation of the gallbladder that develops over hours, usually because a gallstone obstructs the cystic duct. Symptoms include right upper quadrant pain and tenderness... read more , pancreatitis Acute Pancreatitis Acute pancreatitis is acute inflammation of the pancreas (and, sometimes, adjacent tissues). The most common triggers are gallstones and alcohol intake. The severity of acute pancreatitis is... read more Acute Pancreatitis , inflammatory bowel disease Overview of Inflammatory Bowel Disease Inflammatory bowel disease (IBD), which includes Crohn disease and ulcerative colitis, is a relapsing and remitting condition characterized by chronic inflammation at various sites in the gastrointestinal... read more , or various cancers. Tumor markers are best used for monitoring response to treatment in patients with known ovarian cancer

Treatment of Benign Ovarian Masses

  • Monitoring with serial transvaginal ultrasonography for selected cysts

  • Sometimes surgery (cystectomy or oophorectomy)

Many functional cysts < 5 cm resolve without treatment; serial ultrasonography is done to document resolution. If asymptomatic women of reproductive age have simple, thin-walled cystic adnexal masses 5 to 8 cm (usually follicular) without imaging characteristics of cancer, expectant management with repeated ultrasonography (eg, every 6 to 8 weeks) is appropriate.

Benign tumors require treatment. Masses with radiographic characteristics of cancer require exploratory laparoscopy or laparotomy and excision.

If technically feasible, surgeons aim to preserve the ovaries (eg, by cystectomy).

Oophorectomy is done for the following:

  • Fibromas that cannot be removed by cystectomy

  • Cystadenomas

  • Cystic teratomas > 10 cm

  • Other types of cysts that cannot be surgically removed separately from the ovary

  • In postmenopausal women, most cysts or masses, particularly if they are > 5 cm

Key Points

  • Ovarian cysts and benign ovarian tumors are common gynecologic issues.

  • Functional cysts, which develop as part of the menstrual cycle, tend to be small (usually < 1.5 cm in diameter), to occur in premenopausal woman, and to resolve spontaneously.

  • Functional cysts and benign tumors are usually asymptomatic, but sometimes they cause dull or sharp pelvic pain.

  • Excise masses that have radiographic characteristics of cancer (eg, cystic and solid components, surface excrescences, multilocular appearance, irregular shape) or that are accompanied by ascites.

  • Excise certain cysts and benign tumors, including cysts that do not spontaneously resolve.

NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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