A pelvic mass may be detected during routine gynecologic examination. A pelvic mass may be noncancerous or cancerous.
Pelvic masses may originate from gynecologic organs (cervix, uterus, uterine adnexa) or from other pelvic organs (intestine, bladder, ureters, skeletal muscle, bone).
Type of mass tends to vary by age group:
In infants, in utero maternal hormones may stimulate development of adnexal cysts during the first few months of life. This effect is rare.
At puberty, menstrual fluid may accumulate and form a vaginal mass (hematocolpos) because outflow is obstructed. The cause is usually an imperforate hymen; other causes include congenital malformations of the uterus, cervix, or vagina.
In women of reproductive age, the most common cause of symmetric uterine enlargement is pregnancy, which may be unsuspected. Another common cause is fibroids, which may extend outward. Common adnexal masses include graafian follicles (usually 5 to 8 cm) that develop normally but do not release an egg (called functional ovarian 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), or hydrosalpinges. Endometriosis can cause single or multiple masses anywhere in the pelvis, usually on the ovaries.
In postmenopausal women, masses are more likely to be cancerous. Many benign ovarian masses (eg, endometriomas, myomas) depend on ovarian hormone secretion and thus become less common after menopause.
General medical and complete gynecologic histories are obtained.
Findings may suggest a cause for the pelvic mass:
During the general examination, the examiner should look for signs of nongynecologic (eg, gastrointestinal, endocrine) disorders and for ascites. A complete gynecologic examination is done.
Distinguishing uterine from adnexal masses may be difficult. Endometriomas are usually adnexal masses. Advanced endometriosis can manifest as nonmobile cul-de-sac masses. Adnexal cancers, benign tumors (eg, benign cystic teratomas), and adnexal masses due to ectopic pregnancy are often mobile. Hydrosalpinges are usually fluctuant, tender, nonmobile, and sometimes bilateral.
In young girls, pelvic organ masses may be palpable in the abdomen because the pelvis is too small to contain a large mass.
In women of reproductive age, a pregnancy test should be done regardless of stated history. If the pregnancy test is positive, ultrasonography or another imaging test is not always necessary; imaging is necessary when ectopic pregnancy is suspected.
If the presence or origin (gynecologic versus nongynecologic) of a mass cannot be determined clinically, an imaging test can usually do so. Usually, pelvic ultrasonography is done first.
In women of reproductive age, simple, thin-walled cystic adnexal masses that are 5 to 8 cm (usually graafian follicular cysts) do not require further investigation unless they persist for > 3 menstrual cycles or are accompanied by moderate to severe pain.
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 iPhones or Android devices (1).
If ultrasonography does not clearly delineate size, location, and consistency of the mass, another imaging test (eg, CT, MRI) may do so.
Ovarian masses with radiographic characteristics of cancer, such as a solid component, surface excrescences, and irregular shape (which also suggest cancer), require needle aspiration or biopsy. Tumor markers may help in the diagnosis of specific tumors.
Type of pelvic mass 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 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.