Overview

Adnexal tumors and masses are growths of cells that form on the organs and connective tissue around the uterus. Adnexal tumors and masses most often aren't cancer, but they can be cancer.

Adnexal tumors and masses happen in the:

  • Ovaries. The female reproductive system has two ovaries, one on each side of the uterus. They make eggs, called ova. The ovaries also make the hormones estrogen and progesterone.
  • Fallopian tubes. The fallopian tubes connect the ovaries to the uterus.
  • Connective tissue. Connective tissue surrounds and supports the ovaries and fallopian tubes.

Diagnosis of adnexal tumors and masses involves a careful physical exam, imaging tests and blood tests. Treatment depends on the size of the tumor or mass and its cause.

Symptoms

Many adnexal tumors and masses don't cause symptoms. They're often found during a medical exam that's done for another reason.

When adnexal tumors and masses cause symptoms, the symptoms may include:

  • Pain, including pain in the pelvis or belly, painful period cramps that are worse than usual, and painful sex.
  • A feeling of fullness or pressure in the pelvis or belly, or feeling full quickly when eating.
  • Nausea and vomiting.
  • Constipation or bloating.
  • Urinating a lot or having trouble urinating.
  • Bleeding from the vagina that is out of the ordinary.
  • Fever.

When to see a doctor

Make an appointment with a doctor or other healthcare professional if you have any symptoms that worry you.

If you have any of the following symptoms, get emergency medical care right away:

  • Terrible pelvic or belly pain.
  • Pelvic or belly pain that starts quickly.
  • Bleeding from the vagina during the first three months of pregnancy.

Causes

There are many possible causes of adnexal tumors and masses. Causes that are more common include:

  • Cysts. When fluid builds up in an area of the body, the mass that forms is called a cyst. Cysts can happen within the ovaries and fallopian tubes as well as in the connective tissue around them.
  • Endometriosis. Endometriosis happens when tissue that is similar to the inner lining of the uterus grows outside the uterus. It often affects the ovaries, fallopian tubes and the tissue lining the pelvis.
  • Ectopic pregnancy. An ectopic pregnancy happens when a fertilized egg implants and grows outside the main cavity of the uterus, most often in a fallopian tube.

Examples of other health conditions that can lead to adnexal tumors and masses include:

  • Fibrosis. Fibrosis is a condition that happens when connective tissue becomes thick and scarred.
  • Hydrosalpinx. Hydrosalpinx is when fluid blocks a fallopian tube.
  • Infection. An infection may cause pus to build up and form a mass, called an abscess.
  • Ovarian torsion. Ovarian torsion happens when an ovary moves out of its typical position and becomes twisted.
  • Cancer. Most adnexal tumors and masses are not cancer. But some may be cancer that affects the ovaries, fallopian tubes or the tissue around them.

Risk factors

Because so many conditions can cause adnexal tumors and masses, there are many things that can raise the risk of developing them. But it's most important to be aware of factors that can affect the risk of an adnexal tumor or mass being cancer, including:

  • Menopause. People who have gone through menopause are more likely to have an adnexal tumor or mass that is cancer than are people who haven't gone through menopause.
  • Hormone medicines. People who have used infertility medicines with hormones are at a higher risk of a cancerous adnexal tumor or mass. But those who have used hormonal birth control are at a much lower risk of an adnexal tumor or mass being cancer.
  • Family medical history. People with family members who have had breast cancer, ovarian cancer or fallopian tube cancer are at higher risk of developing a cancerous adnexal tumor or mass.
  • Inherited DNA changes. DNA changes that raise the risk of cancer can be passed from parents to children. These changes can greatly raise the risk of getting some cancers. But not everyone with these DNA changes gets cancer.
  • Smoking cigarettes. Cigarette smoking raises the risk of developing an adnexal tumor or mass that is cancer.

March 14, 2025

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  3. AskMayoExpert. Adnexal mass. Mayo Clinic; 2023.
  4. Hoffman BL, et al. Benign Adnexal Mass. In: Williams Gynecology. 4th ed. McGraw Hill; 2020. https://accessmedicine.mhmedical.com. Accessed Dec. 9, 2024.
  5. Ovary. National Cancer Institute. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/ovary. Accessed Feb. 4, 2025.
  6. Fallopian tube. National Cancer Institute. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/fallopian-tube. Accessed Feb. 4, 2025.
  7. Connective tissue. National Cancer Institute. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/connective-tissue. Accessed Feb. 4, 2025.

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