What Is an Adnexal Mass?

Definition, Causes, and Treatment

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An adnexal mass is an abnormal growth that develops near the uterus, usually in the ovaries, fallopian tubes, or surrounding connective tissues. The lump-like mass can be solid or cystic, which means fluid-filled.

Most adnexal masses are benign (noncancerous). Sometimes, though, they can be malignant (cancerous).

Adnexal masses may occur at any age. They are more typically seen in women of reproductive age, however.

This article discusses the different types of adnexal masses and their causes. It also looks at symptoms, diagnosis, and treatment of adnexal masses.

A woman laying in bed in pain from her period
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Types and Causes

There are hundreds of reasons why an adnexal mass may develop. In premenopausal women, they are often associated with ovarian cysts.

There are several different types of ovarian cysts. These include:

  • Follicular cysts: Follicular cysts form when the follicle containing an egg keeps growing instead of rupturing and releasing the egg. People with polycystic ovary syndrome (PCOS) may develop this kind of cyst, but they can also form in people who do not have this condition.
  • Corpus luteum cysts: These cysts form when a group of cells called the corpus luteum keeps growing instead of breaking down after ovulation. 
  • Hemorrhagic cysts: Hemorrhagic cysts happen when there is bleeding into a corpus luteum cyst.
  • Dermoids: These cysts may contain tissue from other parts of the body, including gastrointestinal or lung tissue and skin and hair. 
  • Endometrioma: These cysts contain menstrual blood and endometrial tissue, which is the tissue that lines the uterus. They are found in people with endometriosis, a condition that causes endometrial tissue to grow outside the uterus. 

Most ovarian cysts are non-cancerous and resolve on their own. In postmenopausal women, a healthcare provider should monitor cysts that are larger than 3 cm.

Other causes of adnexal masses include:

Masses larger than 6 cm are more likely to be cancerous than smaller masses. 

Adnexal masses are relatively common. For this reason, healthcare providers have to consider many factors to find the cause and classification of the growth.

Red Flags

Cancer is only one of many possible causes. Red flags are typically raised if:

  • The mass is solid instead of cystic
  • The mass is irregular in shape or density
  • The mass develops before menstruation begins
  • The mass develops after menopause
  • The mass is painful
  • The cyst is extremely large

Symptoms

Adnexal masses don't always cause symptoms. When they do, symptoms may include:

  • Pelvic pain
  • Pain during sex
  • Trouble urinating or frequent urination
  • Bloating
  • Constipation
  • Irregular periods

Diagnosis

You'll need additional tests if your healthcare provider finds an adnexal mass during a physical exam. Imaging tests that can help with the diagnosis include:

A pregnancy test can help diagnose a tubal pregnancy. If ovarian cancer is suspected, a CA 125 test may be ordered. This test measures levels of a protein called cancer antigen 125 in the blood.

If the mass is cystic, your healthcare provider may perform an aspiration to extract fluid with a needle and syringe. However, many healthcare providers will avoid this, especially if cancer is suspected. This is because the extracted fluid may contain malignant cells that can seed other tumors.

Adnexal Mass Treatment

Your initial test results will help determine your treatment. Your healthcare provider may prefer a watch-and-wait approach, regularly monitoring for any changes in the mass. Alternately, it may be best to start immediate interventions. This may include surgical removal of the mass followed by lab evaluations.

If the mass is a tubal pregnancy, emergency treatment may be required. This will prevent a potentially life-threatening rupture, especially if you have symptoms.

In most cases, an adnexal mass will not be a cause for alarm and may never create any health problems.

That said, healthcare providers will pay particular attention to any masses or lesions in or around the ovaries or fallopian tubes. Studies have shown that growths in the fallopian tubes often serve as precursors to a type of cancer called high-grade serous ovarian carcinoma (HGSOC). This cancer may not show up until years after the growth appears. HGSOC accounts for around 75% of all ovarian cancers.

Summary

Adnexal masses are usually not cancerous. They may be associated with ovarian cysts, endometriosis, and polycystic ovary syndrome. Some can be immediately life-threatening, as in the case of an ectopic pregnancy.

Adnexal masses are usually diagnosed with an imaging test like a transvaginal ultrasound or an MRI scan. Depending on the cause, they may be treated with a watch-and-wait approach or with surgery. 

A Word From Verywell

If an adnexal mass is found and cancer is suspected, it is always best to get a second option from a gynecologic oncologist. These healthcare providers are more experienced in the diagnosis, staging, and of treatment of endometrial and ovarian cancers. In general, survival times for women under the care of a gynecologic oncologist will be greater than those treated by a general surgeon.

Even if the adnexal mass turns out to be benign, a gynecologic oncologist will be better able to determine when changes in the growth require more aggressive interventions.

Frequently Asked Questions

  • How fast do adnexal cysts grow?

    It varies. Many grow minimally and resolve on their own within a few weeks. Others grow slowly, averaging less than 2 mm per year. In rare cases, an adnexal cyst may grow rapidly or reach a large size and need to be surgically removed.

  • What is the difference between a tumor and a mass?

    A mass is any lump of material in the body. A tumor is a mass of tissue that occurs from cells growing and dividing or not dying like they should.

  • Do ovarian cysts cause weight gain?

    It's uncommon but unexplained weight gain can be a symptom of ovarian cysts.

10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Steven Vasilev, MD
Dr. Steven Anatol Vasilev is an ovarian cancer expert double board-certified in gynecologic oncology and obstetrics/gynecology.