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Evaluation of the Patient with a Pelvic Mass

D. Ashley Hill, M.D.
Associate Director
Department of Obstetrics and Gynecology
Florida Hospital Family Practice Residency

Overview

The finding of a pelvic mass usually causes great concern for our patients. Understandably, women with a pelvic mass want no stone unturned in the search for a diagnosis. In the era of managed care and cost:benefit ratios, physicians and other health care providers must balance the cost of each test or study with the potential benefits derived from it. This presentation reviews the appropriate evaluation of women who present with a pelvic mass, with a focus on prevention of ovarian cancer. Examples of effective strategies from a cost:benefit viewpoint will be reviewed.

The participant should:

  1. Be able to give a differential diagnosis for major categories of pelvic masses.
  2. Be aware of appropriate strategies for evaluation of pelvic masses.
  3. Understand the various categories of adnexal masses.
  4. Be aware of the incidence and risk factors for ovarian cancer.
  5. Be able to devise a strategy for diagnosing adnexal masses, with an understanding of the cost:benefit ratio of various diagnostic tests.

Before discussing in detail the evaluation of pelvic masses, let's review the differential diagnosis of pelvic masses, then review in more detail the various ovarian masses. Any growth (tumor) of the abdomen or pelvic may enlarge enough to become noticeable, thus producing a mass.

Pelvic Mass Selected Differential Diagnoses

Abdominal: GYN:
  • Peritoneal Cyst
  • Ectopic (abdominal) pregnancy
  • Aortic aneurysm
  • Uterine fibroids
  • Uterine cancer
  • Benign ovarian cyst
  • Ovarian cancer
  • Ectopic pregnancy
  • Fallopian tube cyst
  • Hydrosalpinx
GI:
  • Phlegmon due to ruptured appendix
  • Ruptured diverticulum
  • Bowel malignancy
  • Pancreatic phlegmon
GU:
  • Urinoma from bladder injury
  • Kidney tumor (including pelvic kidney)

Benign Ovarian Cysts-Differential Diagnosis

A number of benign ovarian cysts may enlarge enough to be palpable on either pelvic (bimanual) exam or abdominal exam. Although these are benign, they may become quite large. Cysts the size of golf balls, grapefruits, and even soccer balls are not unusual. Gynecologists tend to gauge the size of the uterus in "weeks of pregnancy" with 12 weeks being about grapefruit size, and 20 weeks being a uterus up to the level of the umbilicus. Ovarian size can be estimated with the following information hi mind:

Ovarian size Analogous object
Normal ovary (2-3 cm) Walnut
4 cm golf ball
6 cm tennis ball
8 cm orange
10-12 cm grapefruit
20 cm basketball

Types of benign ovarian cysts:

Functional Cysts Solid tumors Cystic masses
  • Follicular
  • Corpus luteum
  • Theca lutein
  • Brenner tumor
  • Fibroma
  • Dermoid
  • Cystadenoma
  • Endometrioma

Follicular cysts:

Follicular cysts, sometimes called physiologic cysts, are the most common benign ovarian cyst. Contrary to what most patients think, it is of course perfectly normal to have many ovarian cysts. These follicular cysts are easily identified on vaginal sonography, usually measure a few millimeters to a few centimeters in size, and rarely become symptomatic. If they enlarge in size they may rupture, producing transient abdominal pain. Women on anticoagulant therapy may present with hemoperitoneum that requires operative evaluation and blood products. The most likely diagnosis when confronted with a 4-5 cm cyst on a reproductive-age woman during an annual exam is a follicular cysts. Some decide to reexamine the patient three months later (see below), while others obtain a vaginal sonogram. A clear cyst is reassuring, and a follow-up exam or sonogram in 3 months is indicated. If the cyst is gone, then the patient returns in a year. If it is not, referral for operative evaluation (most likely laparoscopy) is indicated. Some prescribe oral contraceptives, which may decrease the formation of future cysts, but probably do not decrease the size of existing ones.

Corpus luteum cysts

This is another common ovarian cyst. If an egg is not fertilized, the corpus luteum initially grows and produces progesterone, then involutes. A menstrual cycle ensues. In some cases, however, the cyst, which is normally about 4 cm in size, continues to grow, and may become large enough to produce symptoms. Hemoperitoneum from rupture may produce symptoms, or it may twist upon its blood supply, called ovarian torsion, producing acute, extreme pelvic pain usually resulting in immediate self-referral to the emergency department. One should rule out an ectopic pregnancy with a beta-14CG level, and if zero, the patient can usually be followed conservatively as described above for follicular cysts. Patients on anticoagulants may require hospitalization with serial blood counts. Oral contraceptives may prevent recurrence since they block ovulation.

Theca lutein cysts

Theca lutein cysts are the least common of the physiologic ovarian cysts (follicular, corpus luteum, and theca lutein). These are usually bilateral and may result in huge ovaries. These cysts result from ovarian stimulation due to beta-HCG or exogenous gonadotropins, such as infertility medications. Molar pregnancies (hydatidiform mole) tend to produce large levels of HCG, and 50% of these pregnancies result in theca lutein cysts. They are sometimes found in pregnancy, for example during cesarean delivery. If very large, ascites and abdominal distention may occur they may bleed profusely if ruptured, so most gynecologists advocate leaving them alone if found during cesarean section. They will regress once HCG levels decrease. A related ovarian mass is the luteoma of pregnancy, which can cause masculization of the mother (30% of cases) and female fetus. These also regress after delivery.

Brenner Tumor

This is a benign ovarian mass that is usually asymptomatic and solid and is most common in women age 40-60 years. These are solid tumors that are most often unilateral and are usually about 4-5 cm in size. 90% are found incidentally during a pelvic operation. Treatment consists of oophorectomy.

Fibroma

This is the most common solid ovarian mass. These are almost always benign (1% malignancy rate) and may vary dramatically in size. Most are 6 cm in diameter, but some may weigh over 50 pounds. Meig's syndrome is asitias and hydrothorax caused by an ovarian fibroma. Treatment of fibroma is oophorectomy.

Dermoids

Dermoids, also called teratomas, are germ cell tumors that actually begin growing in utero. These are fascinating tumors that usually attract a crowd when opened in the operating room. The word "dermoid" means monstrous growth and is an apt description of these solid and cystic ovarian masses. 98% of dermoids are benign cystic masses that arise from a totipotential stem cell in the fetus. Their chromosomal makeup is 46XX, and they can contain tissue from all 3 germ layers, including hair, teeth, cartilage, bone, glial cells, muscle fibers, sebaceous and sweat glands, and epithelium of the respiratory tract. Sometimes thyroid tissue is present and can cause symptomatic hyperthyroidism (struma ovarii). The most common finding is an abundant amount of hair and sebaceous material. Leakage of this material into the abdominal cavity, which occurs in about 1% of cases, can cause a severe chemical peritonitis and lead to massive pelvic adhesions with resultant pain and bowel obstruction. Most dermoids are asymptomatic and unilateral in 85% of cases. They are treated by cystectomy in young women or oophorectomy in older women.

Cystadenoma

Cystadenomas can be either serous or mucinous, and can grow to enormous sizes. Serous tumors are typically filled with a straw-colored fluid and can be either uni- or bilateral. Mucinous tumors may grow to over 30 cm, and are filled with a thick mucous that can cause adhesions and bowel obstruction if spilled into the peritoneal cavity. Diagnosis is by sonogram and surgery, often via laparotomy due to the increased size. Treatment is surgical excision by unilateral or bilateral salpingophorectomy. Both tumor types may be borderline, in which case surgical treatment depends on the age and reproductive history of the patient.

Endometrioma

Endometriomas are ovarian cysts filled with "old" blood, due to proliferation of endometriosis implants on the ovary. They typically become symptomatic at around 4-5 cm. Endometriomas are often called "chocolate cysts" because they tend to spill a chocolate-appearing fluid when ruptured. Diagnosis is by examination and ultrasound, and treatment consists of laparoscopic excision or oophorectomy.

Ovarian Cancer

There are 4 main categories of Ovarian cancer, as described below. Epithelial tumors are the most common, while germ cell tumors tend to arise in younger women or children. The most common type of epithelial cancer is the serous cystadenocarcinoma, whereas the most common malignant germ cell tumor is the dysgerminoma.

Ovarian cancer is the second most common gyn malignancy, behind endometrial carcinoma. About 30,000 cases of ovarian cancer are diagnosed annually. Unfortunately, most ovarian cancers are diagnosed at a late stage, therefore survival is poor. Incidence rises with age, increasing markedly past age 50. The lifetime incidence is 1:70, although this can increase dramatically with a strongly positive family history.

Epithelial tumors
(Most common above age 50)
*denotes benign tumor type

Serous cystadenocarcinoma
Mucinous cystadenocarcinoma
Endometrioid carcinoma
Serous and mucinous cystadenomas*
Brenner tumors*

Germ Cell tumors
(Usually in patients under age 30. 1/3 of those in women < 21 are malignant).

Immature (malignant) teratoma (dermoid)
Mature dermoid*
Dysgerminoma
Endomdermal sinus tumors
Embryonal carcinoma
Choriocarcinoma
Polyembryoma

Sex cord-stromal tumors
(Only 6% of ovarian neoplasms, these tend to cause hormonal symptoms such as hirsutism).

Granulosa-Theca Cell tumors
Sertoli-Leydig tumors
Thecomas and Fibromas*

Metastatic Ovarian tumors
Krakenberg's tumor (from the GI tract)
Breast metastases

Associations with Ovarian Cancer

Increases risk Decreases risk
Increased age
Family history
Infertility
Nulliparity
Ovulation (? ovulation induction)
Talc?
Oral contraceptive use
Breast-feeding
Pregnancy
Prior tubal ligation ?

Evaluation of the Pelvic Mass

There are a number of possible disorders that can cause a pelvic mass. Some are common, while others are quite unusual or even rare. When confronted with a female patient with a pelvic mass, the first step in evaluating the patient is, of course, a good history. Important historical points should include:

  • Is there pain?
  • Any change in bowel or bladder habits?
  • Is there a family history of any similar problems, or malignancy?
  • Are you having any pain in your flanks, or recent kidney infections?
  • Are your periods regular? Any pregnancies? Pain with intercourse?

The physical exam should include visualization and palpation of the abdomen, looking for adenopathy, ascites, a palpable mass, CVA tenderness, and abdominal pain. A pelvic exam should look for compression of the cervix against one side of the vagina (mass effect), an adnexal or uterine enlargement or "fullness," tenderness, associated vulvar or vaginal lesions, and rectovaginal compression or blood in the rectum.

The next step is usually an imaging study, such as ultrasound (sonogram), CAT scan, MRI, or barium enema. The type of study obtained will depend on one's physical exam findings, and is discussed in more detail later, but, in general, the first test should be an ultrasound. From a cost:benefit perspective, the following table illustrates the value of each test. Please note that most gynecologists prefer ultrasound as the study of choice for evaluation of pelvic pathology. CAT scans are uncommonly ordered by gynecologists due to their increased cost and decreased sensitivity compared to ultrasounds. Intravenous pyelograms (IVP) and barium enemas (BE) are sometimes used as second-line tests to rule out ureteral or bowel involvement, respectively.

Study Est Cost($) Benefits Drawbacks
Ultrasound 150.00 Directly images the adnexa and uterus Cannot image upper abdomen
CAT scan 300-1000 Can obtain images of entire abdomen and pelvis, including the ureters Usually not as sensitive for adnexal or uterine pathology
MRI 1000 Good technique for fibroids and adenomyosis Appears safe in pregnancy Expensive Other tests usually adequate at much less cost
BE 200 Often a useful second-line test-to rule out bowel involvement Not usually helpful for diagnosis of mass
IVP 200 Evaluates potential ureteral involvement or alteration course of ureter(s) Mass may show on IVP, but not sensitive enough to determine in most likely diagnosis of mass

If pelvic exam and ultrasound suggest an abdominal mass (i.e. peritoneal cyst) or GI tumor, a CAT scan may be indicated. Referral to a gastroenterologist or general surgeon would be indicated.

If exam and ultrasound suggest fibroids, then expectant management or referral to a gynecologist is indicated if symptomatic. Small and asymptomatic fibroids can be followed with annual pelvic exams. Repeat ultrasound is indicated if the fibroids become symptomatic or increase rapidly in size.

The most difficult management strategy occurs when an adnexal mass is diagnosed. Is it benign, or is it cancer? There are significant health and medicolegal issues involved, and most are reluctant to "watch" an adnexal mass over time. Some order multiple ultrasounds and CAT scans, even for small, clear cysts, in young women, driving up the cost of what is almost certainly a benign process. What, then, is an acceptable management policy for the adnexal mass?

The Adnexal Mass

Children

Girls with adnexal masses require referral to a gynecologist or gynecologic oncologist to rule out a dysgerminoma or other malignant germ cell tumor.

Adolescents

Most adnexal masses in this age group are functional cysts, such as follicular cysts, or corpus luteum cysts. Most will be under 5 cm, although some will grow to 10 cm. The prototype nonfunctional cyst for this age group is a germ cell tumor, the dermoid (mature teratoma).

If a cyst is palpated, obtain a vaginal ultrasound to determine if the cyst is simple (clear), solid, or complex (often a combination of cystic and solid). Solid tumors require surgery. Simple cysts, especially those under 6 cm, may be observed for a few menstrual cycles. They usually resolve. If not, surgery may be indicated. Complex cysts in this age group are most often corpus luteum cysts partially filled with blood. They, too, can be observed for a few cycles. If they increase in size or do not resolve over 2-3 months, surgery may be indicated. If they are large (i.e. 10 cm) then many would obtain the tumor markers associated with germ cell tumors, such as an HCG level (pregnancy or choriocarcinoma), an LDH (dysgerminoma), or alpha fetoprotein (AFP; endodermal sinus tumor). As discussed later, CA-125 levels lack sensitivity in this age group, and I do not advocate obtaining them in premenopausal women with an adnexal mass.

Age 20-45

The most common neoplasm in this age group is still the functional cyst. Other ovarian neoplasms, including cancer, are possible. Thus, a thorough pelvic exam and a vaginal ultrasound are usually necessary for evaluation. Simple (clear) cysts can be managed by observation with repeat pelvic exam (in thin patients) and pelvic exam with vaginal ultrasound if necessary. If unresolved over 3 months, most would advocate operative intervention. If the cyst is complex and the patient is not on oral contraceptives, she may have a corpus luteum cyst. If the monographic appearance is that of a corpus luteum cyst then observation may be indicated. However, if the cyst is large (i.e. greater than 6 cm or so) or the patient is already on oral contraceptives, she may need laparoscopic evaluation.

Peri- and Post menopausal women

These women are at increased risk of malignancy, but most adnexal masses in this age group are still. benign. The size of the tumor plays a role, as one study showed that only 1 in 32 tumors less than 5 cm in this age group were cancerous. However, as the size increased to greater than 10 cm, 40/63 were malignant. These patients also need a good pelvic exam and a vaginal ultrasound. Serum CA-125 levels are often useful in this age group. However, this test is not sensitive enough to be used as a screening tool. Some researchers have suggested that it would cost over 10 billion dollars per year to "screen" all U.S. postmenopausal women with a CA-125 level and a vaginal ultrasound. 80% of ovarian epithelial cancers express CA-125, but other situations may lead to increased levels of this marker, including smoking, endometriosis, abdominal surgery, pregnancy, fibroids, liver disease, and benign, hemorrhagic ovarian cysts. Nomepithelial tumors may not express CA-125.

One of my colleagues in Orlando evaluated CA- 1 25 levels, vaginal sonogram, and pelvic exam and determined that in premenopausal women the pelvic exam and sonogram were successful at predicting a benign condition, whereas in postmenopausal patients the addition of a CA-125 level increased the predictive value for benign disease. Since simple (functional) cysts can be found in postmenopausal women, there is a place for observation in selected patients. The combination of a reassuring pelvic exam, normal CA-125 level, and a vaginal sonogram that does not suggest malignancy may lead to observation or laparoscopic management. However, this should usually be managed by a gynocologist or gynocologist. Patients with large masses, abnormal CA-125 levels, a non-reassuring pelvic exam, or a suspicious vaginal ultrasound usually require an exploratory laparotomy via a vertical incision, and, if necessary, a total abdominal hysterectomy and removal of both ovaries. If cancer is found, a staging laparotomy, consisting of a hysterectomy/oophorectomy, omentectomy, pelvic and paraaortic lymphadenectomy, appendectomy and biopsy of peritoneal surfaces is the usual treatment of choice. In most cases this is followed by 6 or more months of chemotherapy.

Summary

The evaluation of adnexal masses depends on the patient's age, the size of the tumor, her symptoms (if any), the findings on a vaginal sonogram, and, in postmenopausal patients, the results of a CA-125 level, which currently should be under 35. In younger women most simple cysts can be managed by observation alone over 3 months, with a follow-up pelvic exam and, if necessary, a vaginal ultrasound. in postmenopausal women most cysts need operative intervention, whether by laparoscopy (if tests and exam are reassuring) or laparotomy (if CA-125 is elevated and ultrasound or pelvic exam is suspicious). When in doubt a second opinion or referral to a gynecologist is in order, and in cases where the cyst does not resolve or actually grows, surgical intervention is the norn.

References

Parker WH. The case for laparoscopic management of the adnexal mass. Clin Obstet Gynecol 1995;38:362-369.

Finkler N, Benacerraf B, Lavin P, Wojciechowski C, Knapp R. Comparison of serum CA-125 clinical impression, and ultrasound in the preoperative evaluation of ovarian masses. Obstet Gynecol. 1988;72:659-664.

Shalev E, Eliyahu S, Peleg D, Tsabari A. Laparoseopic management of adnexal cystic masses in postmenopausal women. Obstot Gynecol. 1994;83:534.

Goldstein S, Subramanyam B, Snyder J, Beller U, Raghavendra N, Beckman M. Te postmenopausal cystic adnexal mass: the potential role of ultrasound inconservative management. Obstet Gynecol 1989;73:8.

Granal CO. Ovarian cancer: unrealistic expectations. N Engl J Med 1992;327:197.

Goldstein SR. Incorporating endovaginal ultrasonography into the overall gynecologic examination. Am J Obstet Grecol 1990; 162:625-632.

Mishell D, Stenchever M, Droogemueller W, Herbst A (eds). Comprehensive Gynecology, 3rd ed. Mosby: St. Louis.