Adnexal Mass

What Is It, Causes, Treatment, and More

Author: Nikol Natalia Armata

Editors: Ahaana Singh, Ian Mannarino, MD, MBA

Illustrator: Jillian Dunbar

What is an adnexal mass?

An adnexal mass refers to a growth that develops in the female pelvic region. Adnexal masses occur near the uterus, usually in the ovaries, fallopian tubes, or connecting tissues. These growths can originate from either the reproductive system or nearby pelvic organs, such as the intestines or the urinary bladder. Adnexal masses usually are not cancerous (i.e., benign), but they can be cancerous (i.e., malignant) in some cases.

What causes an adnexal mass?

There are multiple causes of adnexal mass development. Gynecologic causes, meaning that masses originate from the reproductive system, are the most common. In some cases, however, there may be non-gynecologic causes that involve the digestive or urinary system

Adnexal masses are usually associated with the female reproductive system and occur more frequently in individuals of childbearing ages. In fact, ectopic pregnancy is a very common cause of adnexal masses. An ectopic pregnancy is when an embryo implants somewhere other than in the uterine cavity—most frequently in the fallopian tube. In cases of pregnant individuals for whom ectopic pregnancy has been ruled out, adnexal masses are usually benign and occur as a result of hormonal changes identified during pregnancy. 

In non-pregnant individuals, the most common types of gynecologic adnexal masses are  functional ovarian cysts (i.e., luteal cysts), which form on the surface of the ovary after ovulation occurs. Notably, the presence of such cysts increases the risk of ovarian torsion, a medical emergency that presents when the ovary rotates around its ligaments and interferes with the blood supply. Additionally, adnexal masses may present as multiple small cysts on enlarged ovaries (i.e., polycystic ovaries), which is characteristic of polycystic ovary syndrome (PCOS). Other adnexal masses include leiomyomas -- benign, fibrous tumors usually occurring in the uterus -- and endometriomas, which are cysts that form when endometrial tissue grows in or around the ovaries. Pelvic inflammatory disease or other causes of tubo-ovarian abscesses (i.e., collections of pus in the ovaries and fallopian tubes) can also cause adnexal masses. If the mass is suspected to be malignant, ovarian cancer is the most common cause. 

On the other hand, non-gynecologic adnexal masses often originate from the gastrointestinal or urinary system. Common types of these adnexal masses include inflammatory masses of the appendix, colorectal cancer, as well as pelvic kidneys, which occur when the kidneys do not  fully ascend during fetal development. Lastly, breast and colon cancer, when spread to other organs, can metastasize in the pelvis and create adnexal masses.

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Does having an adnexal mass mean cancer?

Adnexal masses are not necessarily cancerous. They may be malignant in some cases, but most commonly, adnexal masses are benign, or not cancerous.

What are the symptoms of having an adnexal mass?

Symptoms associated with adnexal masses often differ depending on what caused the mass to form. Pelvic pain is a common symptom, and it can suggest many different causes, including ectopic pregnancy, ovarian torsion, or inflammatory disease. Pain may be accompanied by bloating or a strong desire to urinate due to the pressure solid masses can apply on neighboring organs. In cases of endometriomas, leiomyomas, or polycystic ovaries, unusual vaginal bleeding and changes in menstruation may also be symptoms. Lastly, dyspareunia, or genital pain during sexual intercourse, may be experienced by individuals with adnexal masses. 

How is an adnexal mass diagnosed?

When evaluating adnexal masses, a review of medical history, with a detailed gynecologic and family history, and a careful review of symptoms are often necessary. 

Moreover, a pregnancy test should be performed for every individual of childbearing age. In addition, if infection is suspected, blood tests may be performed to investigate for gonorrhea, chlamydia, and other sexually transmitted infections. Blood tests can also show potentially elevated serum levels that may be indicative of endometriosis, pregnancy, pelvic inflammatory disease, and non-gynecologic cancers.

A pelvic examination with transvaginal ultrasonography, when an ultrasound probe is inserted into the vaginal canal, may be helpful in order to better view the individual’s female reproductive system. In some cases, further imaging, such as computed tomography (CT) or magnetic resonance imaging (MRI), may be suggested.

How is an adnexal mass treated?

Treatment options for adnexal masses vary depending on the specific diagnosis. Some masses can be treated conservatively, and others may require surgery. 

Observation is generally recommended when the appearance of the adnexal mass on ultrasonography suggests a benign growth. Most of the time, cysts up to 10 cm (approximately four inches) in diameter are benign and self-limiting. With appropriate medical follow-up, these masses can be safely monitored using frequent imaging. 

Surgical intervention is preferred for symptomatic masses or for suspected malignancy, based on the results of imaging and serum testing. For benign masses, minimally invasive techniques are the preferred method of intervention. One such method is laparoscopy, which allows the surgeon to access the inside of the abdomen through small incisions in the skin. In cases of larger or malignant cysts that cannot be extracted laparoscopically, open surgery may be required.

What are the most important facts to know about adnexal masses?

Adnexal masses include different types of growths near the uterus, in the ovaries, fallopian tubes, or connecting tissues. In most cases, they are benign, but in some instances, they may be malignant. The causes of adnexal masses vary and can be either gynecologic or non-gynecologic. Common symptoms associated with adnexal masses include irregular vaginal bleeding, bloating, dyspareunia, urinary symptoms, and pelvic pain. Diagnosis of adnexal masses involves medical history review and physical examination. Blood tests and imaging may be necessary for diagnosis in rare cases. Treatment for adnexal masses largely depends on the underlying cause and can be either conservative or surgical. 

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Related links

Ectopic pregnancy
Ovarian cysts, cancer, and other adnexal masses: Clinical practice
Ovarian cysts and tumors: Pathology review

Resources for research and reference

Alalade A, Maraj H. Management of adnexal masses in pregnancy. The Obstetrician & Gynaecologist. 2017;19(4):317-325. doi:10.1111/tog.12417.

American College of Obstetricians and Gynecologists’ Committee on Practice Bulletins—Gynecology. Practice bulletin no. 174: Evaluation and management of adnexal masses. Obstetrics and Gynecology. 2016;128(5):e210–e226. doi:10.1097/AOG.0000000000001768.

Biggs W, Marks S. Diagnosis and management of adnexal masses. American Family Physician. 2016;93(8):676-681. Published April 15, 2016.

National Cancer Institute. Adnexal mass. In NCI Dictionary of Cancer Terms. Accessed January 9, 2021.