The female pelvic cavity contains the upper female reproductive tract (cervix, uterus, ovaries, fallopian tubes); the adnexa refers to the ovaries, fallopian tubes, and surrounding connective tissues. The pelvic cavity also contains the intestines, bladder, and lower ureters. A pelvic mass may originate from any of these structures.
A pelvic mass may be detected during routine gynecologic examination or an imaging test. A pelvic mass may be noncancerous or cancerous.
Etiology of Pelvic Mass
Pelvic masses may originate from the upper female reproductive tract (cervix, uterus, fallopian tubes, ovaries) or from other pelvic structures (intestines, bladder, ureters).
Type of mass in the female reproductive tract tends to vary by age group:
In infants, in utero maternal hormones may stimulate development of follicular ovarian cysts in a fetus or during the first few months of life. This effect is rare.
In children, prepubertalmasses are uncommon. Ovarian masses may be follicular ovarian cysts or, rarely, benign or malignant tumors.
In women of reproductive age, the most common cause of symmetric uterine enlargement is pregnancy. Another common uterine mass is a uterine fibroid, which sometimes extends to the cervix or uterine connective tissues. Adnexal masses are often related to the menstrual cycle; they include follicular ovarian cysts (follicles that develop normally but do not release an egg) and corpus luteal cysts. These cysts often resolve spontaneously within a few months. Adnexal masses may also result from ectopic pregnancy, ovarian cancer, fallopian tube cancer, benign tumors (eg, benign cystic teratomas), endometriosis, hydrosalpinges, or a tubo-ovarian abscess.
In postmenopausal women, a new or growing pelvic mass is more likely to be cancerous. Many benign ovarian or uterine masses (eg, endometriomas, adenomas, fibroids) depend on ovarian hormone secretion and thus do not develop or enlarge after menopause. Metastatic cancer of the breast, colon, or stomach may first manifest as an adnexal mass.
Evaluation of Pelvic Mass
History
General medical and complete obstetric and gynecologic histories are obtained.
Symptoms or findings may suggest a cause for the pelvic mass:
Vaginal bleeding and pelvic pain with a positive pregnancy test: Ectopic pregnancy, another obstetric complication, or, rarely, gestational trophoblastic disease
Dysmenorrhea: Endometriosis, adenomyosis, or uterine fibroids
Fever and pelvic pain: Tubo-ovarian abscess
Postmenopausal bleeding: Increased suspicion of uterine cancer
Hormonal effects, such as precocious puberty, virilization, or abnormal uterine bleeding: A masculinizing or feminizing ovarian tumor
Examination
During the general examination, the examiner should look for signs of nongynecologic (eg, gastrointestinal, urologic, endocrine) disorders and for ascites. If malignancy is suspected, evaluation for groin or supraclavicular lymphadenopathy is indicated.
A complete gynecologic examination is done. Distinguishing uterine from adnexal masses may be difficult. If ectopic pregnancy is suspected, excess pressure during examination is avoided to prevent rupture. Advanced endometriosis can manifest as nonmobile cul-de-sac masses. Cervical motion tenderness occurs in pelvic infection (and appendicitis). Nonmobile masses may be inflammatory (eg, due to endometrioma, hydrosalpinx, or tubo-ovarian abscess) or malignant. Hydrosalpinges are usually fluctuant, tender, nonmobile, and sometimes bilateral.
In early pregnancy or in young girls, pelvic organ masses may be palpable in the abdomen because the space in the pelvis is too small to contain a large mass.
Testing
If women of reproductive age have a pelvic mass, a pregnancy test should be done regardless of menstrual or sexual history. If a pregnancy test is positive, ultrasonography or another imaging test is not always necessary; imaging is necessary when pelvic pain or vaginal bleeding is present.
If a suspected mass is not detected during examination or the cause cannot be determined, an imaging test is done. Usually, pelvic ultrasonography is done first.
In women of reproductive age, simple, thin-walled cystic adnexal masses that are 3 to 10 cm (usually follicular cysts) do not require further investigation unless they persist for> 3 menstrual cycles or are accompanied by moderate to severe pain (1).
The International Ovarian Tumor Analysis (IOTA) group developed the Simple Rules to preoperatively assess risk of cancer in women who have ovarian or other adnexal tumors that are thought to require surgery. Classification is based on the presence or absence of 10 ultrasound features and has a higher sensitivity and specificity than other classification scores. In 2016, the IOTA Simple Rules were updated to include a risk calculation tool (SRrisk), which can be used on mobile devices (2).
If ultrasonography does not clearly delineate size, location, and consistency of the mass, another imaging test may do so. MRI is typically used for further evaluation of the mass; CT is useful for evaluating suspected metastases.
By permission of the publisher. From Hricak H, Coakley F, Bergman A. In Atlas of Cancer. Edited by M Markman, RR Barakat, and WJ Hoskins. Philadelphia, Current Medicine, 2002.
Radiographic characteristics that suggest cancer include a solid component (particularly those with a blood supply), thick septations, surface excrescences, ascites, and additional intraabdominal masses. Suspected adnexal masses are evaluated with surgical exploration because biopsy may spread malignant cells. Tumor markers may help in the diagnosis of specific tumors. Suspected uterine masses may be evaluated with endometrial biopsy and/or surgical exploration.
By permission of the publisher. From Hricak H, Coakley F, Bergman A. In Atlas of Cancer. Edited by M Markman, RR Barakat, and WJ Hoskins. Philadelphia, Current Medicine, 2002.
Evaluation references
1. Andreotti RF, Timmerman D, Strachowski LM, et al: O-RADS US Risk Stratification and Management System: A consensus guideline from the ACR [American College of Radiology] Ovarian-Adnexal Reporting and Data System Committee. Radiology 294 (1):168–185, 2020. doi: 10.1148/radiol.2019191150 Epub 2019 Nov 5.
2. International Ovarian Tumor Analysis: IOTA Simple Rules and SRrisk calculator to diagnose ovarian cancer. Accessed 1/22/22.
Key Points
Type of mass in the female reproductive tract tends to vary by age group.
In women of reproductive age, the most common cause of symmetric uterine enlargement is pregnancy; other common causes of pelvic masses are uterine fibroids and functional ovarian cysts.
In postmenopausal women, masses are more likely to be cancerous.
In women of reproductive age, do a pregnancy test.
If clinical evaluation is inconclusive, do an imaging test; usually, pelvic ultrasonography is done first.
