Ovarian mucinous cystadenoma: evaluating the pelvic mass

Author: Daniel J. Hein, Greg Abbott
Date: Oct, 1993

Ovarian masses, particularly mucinous cystadenomas, are among the largest tumors in humans.[1,2] An ovarian mucinous cystadenoma as large as 149 kg (328 lb) has been reported.[3] Mucinous cystadenomas usually occur in younger patients. In 95 percent of cases, the tumor is unilateral. Malignant transformation is uncommon, but may occasionally occur. Because of this potential, these tumors must be histologically classified and appropriately treated.

Mucinous cystadenomas are usually asymptomatic, but patients may present because of an abdominal mass or nonspecific abdominal discomfort.[4,5] Therefore, when evaluating a patient for nonspecific abdominal complaints, a gynecologic examination must always be performed and a high index of suspicion for pelvic pathology must be maintained.

Illustrative Case

A 23-year-old woman (gravida 0, para 0) presented with a complaint of an enlarged abdomen. She had noticed that her clothes felt tight, and she had been dieting in an attempt to reduce the size of her adbomen. She reported regular monthly menses without cramping or vaginal discharge. Her last normal menstrual period was four weeks previously. She denied symptoms of pregnancy and had no bowel or bladder symptoms.

Abdominal examination revealed dullness to percussion below the level of the umbilicus. Palpation below the umbilicus revealed a firm abdomen and a palpable mass.

On gynecologic examination, the cervix was difficult to locate, being extremely posterior and deviated to the right. The cervix appeared distorted and elongated, with a closed os. On bimanual examination, the cervix was fixed and firm, the adnexae were not palpable, and a pelvic mass was identified. The mass was consistent with an 18-week-size uterus.

Laboratory tests included a negative urine pregnancy test, a class I Papanicolaou smear, a normal complete blood count and negative tests for gonorrheal, chlamydial, trichomonal and candidal infections. Ultrasonogram of the pelvis and an abdominal radiograph (KUB) demonstrated the mass (Figures 1 and 2).

Exploratory laparotomy revealed a large cystic structure arising from the right adnexa. A right salpingo-oophorectomy was performed, and a 3.97 kg (8 lb, 12 oz), 30 cm x 24 cm x 20 cm mucinous structure was removed (Figure 3).

Frozen sections of the specimen revealed no malignancy. Peritoneal washings of the paracolic gutters showed no malignant cells. The specimen was confirmed to be a benign mucinous cystadenoma, class B1, according to the International Federation of Gynecology and Obstetrics (FIGO) classification system. Figure 4 is a stained section of the specimen.

Evaluating a Pelvic Mass

When evaluating women with nonspecific abdominal complaints, a thorough abdominal and gynecologic examination must always be performed, with attention to the adnexae. The U.S. Preventive Services Task Force does not recommend routine screening of asymptomatic women for ovarian malignancy. However, examination of the adnexae is recommended when a pelvic examination is performed.[6]

Evaluation of a pelvic mass should be performed in a cost-effective manner. One approach to the work-up of a patient with a pelvic mass is given in Figure 5. The evaluation should begin with a thorough history and the physical examination.

Although further testing is necessary in the differential diagnosis of a pelvic mass, the history and physical examination often provide important clues. For example, a distended, neurogenic bladder can present as a mass in patients who have had a stroke or who have diabetes. Catheterization may result in disappearance of the mass. An anteriorly placed uterus or a displaced rectum suggests a retroperitoneal mass. A right-sided mass that seems higher than the ovary suggests a cecal or appendiceal mass. Masses on the left side may also originate in the rectosigmoid. Bilateral pelvic masses are more likely to represent ovarian malignancy.

When a mass cannot be localized by physical examination, ultrasonography may be helpful, and color flow imaging may hel define the character of the mass. Magnetic resonance imaging (MRI) and computer tomographic (CT) scanning are costly and should be limited to patients in whom initial diagnostic studies have not yielded a clear diagnosis. CT scanning and MRI are helpful in cancer staging.

The epithelial tumor marker CA-125 is increasingly being used in preoperative decision making about pelvic masses. CA-125 was originally intended to be used as a marker for following the course of epithelial ovarian cancers postoperatively. However, it is now used by some physicians preoperatively. A level greater than 35 units per mL raises the suspicion of malignancy. However, this level was chosen arbitrarily, and a negative CA-125 result does not exclude the presence of malignancy. At a cut-off value of 35 units per mL, 1.4 percent of healthy control subjects, 6.3 percent of women with benign disease and 28.5 percent of patients with nongynecologic malignancies will have elevated levels. However, only 82 percent of known epithelial malignancies are associated with elevated CA-125 levels.[7]

Currently, the most accurate preoperative evaluation of pelvic masses is accomplished with a combination of history, determination of menopausal status, physical examination, ultrasonography and, if the mass is ovarian, a CA-125 level.[8] The differential diagnosis for pelvic masses is shown in Table 1.[9]

TABLE 1Diffrential Diagnosis of Pelvic MassesOrgan Cystic mass Solid massOvary Functional cyst Neoplasm Neoplastic cyst Benign Benign Malignant Malignant EndometriosisFallopian Tubo-ovarian abscess Tubo-ovarian absces Hydrosalpinx Ectopic pregnancy Parovian cyst NeoplasmUterus Intrauterine pregnancy Pedunculated or interligamentous myoma Endometrial cancerBowel Sigmoid or cecum Diverticulitis distended with gas Ileitis and/or feces Appendicitis Colon cancerOther Distended bladder abdominal wall hematoma Pelvic kidney or abscess Urachal cyst Retroperitoneal neoplasm

Classification and Epidemiology

In the illustrative case, the pelvic mass was an ovarian mucinous cystadenoma, which is a class B tumor in the FIGO classification system (Table 2).[10] Ovarian mucinous cystadenomas are the second most common benign ovarian neoplasms, accounting for about 20 percent of ovarian neoplasms. They are usually found in young patients and are before puberty or after menopause.

TABLE 2Histologic Classification of Ovarion Neoplasms(*)A. Serous cystomas1. Serous cystadenomas, benign2. Serous cystadenomas with proliferation of epithelial cells and nuclear abnormalities but no infiltrative destructive growth (low potential for malignancy)3. Serous cystadenocarcinomasB. Mucinous cystomas1. Mucinous cystadenomas, benign2. Mucinous cystadenomas with proliferation of epithelial cells and nuclear abnormalities but no infiltrate destructive growth (low potential for malignancy)3. Mucinous cystadenocarinomasC. Endometroid tumors, similar to adenocarcinoma of the endometrium1. Endometroid cysts, benign2. Endometroid tumors with proliferation of epithelial cells and nuclear abnormalities but no infiltrative destructive growth (low potential for malignancy)3. Endometroid cystadenocarcinomasD. Mesonephric tumors1. Benign mesonephric tumors2. Mesonephric tumors with proliferation of epithelial cells and nuclear abnormalities but not infiltrative destructive growth (low potential for malignancy)3. Mesonephric cystadenocarcinomasE. Concomitant carcinoma, unclassified carcinoma (tumors that cannot be classified as stage I, II, III or IV)(*) - Classification system of the International Federation ofGynecology and Obsterics.

Ovarian mucinous cystadenomas are generally asymptomatic. Patients may, however, present with generalized nonspecific complaints of abdominal discomfort or enlargement or edema of the legs. If the tumor is massive enough, decreased respiratory excursion and tachypnea may occur as a result of decreased respiratory volume and compression of the diaphragm. Patients may complain of dyspnea when lying supine, which may cause sleep disturbances. These massive tumors can compress the inferior vena cava, resulting in edema of the lower extremities and collateral venous return, indicated by dilated abdominal veins. Upward displacement of the xiphoid cartilage and a tense abdomen may also be evident.

Other complications that can arise from such massive tumors include malnutrition from dieting as the patients tries to reduce the size of her abdomen, difficulty with ambulation and uterine prolapse.[2,3] Rupture of mucinous cystadenomas can lead to pseudomyxoma peritonei. In this conditions, mucinous material accumulates in the abdominal cavity, and recurrent paracentesis is required for drainage.[4]

Ovarian mucinous cystadenomas may be functional, producing either estrogen or androgens[11] and causing hyperplasia of the endometrium or hirsutism. Gastrinsecreting cystadenomas have been associated with Zollinger-Ellison syndrome and may be manifested by diarrhea and gastric and duodenal ulcers.[12]


Ovarian mucinous cystadenomas tend to be unilateral, with approximately 5 percent presenting bilaterally.[13] They may appear as rounded, ovoid or irregularly lobulated growths with a smooth outer surface of whitish or bluish hue. The wall of the tumor may be so thin that it is transparent.

The content of the cyst is generally a clear, viscous, thick fluid, which appears chocolate brown in color when mixed with blood. Although adhesions to surrounding organs may be present, they usually represent inflammatory reactions, rather than malignant extension. These tumors may be strikingly multiloculated with a honeycomb appearance.[14]

Figure 4 illustrates the histologic characteristics of a benign mucinous cystadenoma: a single layer of nonciliated columnar epithelial cells with normal appearing basal nuclei and few nitoses per high-powered field.[13] In contrast, the histologic characteristics of mucinous cystadenocarcinomas include a piling up of the epithelium, many mitoses per high-powered field, formation of papillae, atypia of epithelial cells with invasion of the stroma and formation of solid masses.[15-17]

Malignant transformation of these tumors is uncommon. A pathologic continuum exists between the completely benign mucinous cystadenoma and the clearly malignant mucinous cystadenocarcinoma.[16] Some authors use the morphologic grouping of "benign," "borderline" and "malignant."[15] Pathologically, it may be difficult to discriminate between these groups, and the pathologist must investigate the level of differentiation of the epithelial components, stroma and capsule.[15,16] Because of the complex loculation (Figure 6), the entire tumor must be examined thoroughly.

Treatment is traditionally surgical and consists of total abdominal hysterectomy and bilateral salpingo-oophorectomy, with careful exploration and staging if frozen sections of the tumor show malignancy. However, in the young patient who wishes to maintain fertility, a unilateral salpingo-oophorectomy is adequate therapy if the tumor is benign on frozen section.[5,16,18] The contralateral ovary should be examined for cystadenomas or other lesions. In one study, a 100 percent survival rate was reported in patients who underwent conservative unilateral salpingo-oophorectomy.[19]


[1.] Symmonds R, Spraitz A Jr, Koelsche G. Large ovarian tumor: report of a case. Obstet Gynecol 1963; 22:473-7. [2.] Beacham WD, Webster HD, Lawson EH, Roth LM. Uterine and/or ovarian tumors weighing 25 pounds or more. A review of the literature in English since 1946. Am J Obstet Gynecol 1971;109:1153-61. [3.] Spohn AE. Multicystic ovarian tumor weighing 328 pounds. Texas J Med 1905;1:273. [4.] Cohen I, Altaras M, Lew S, Jaffe R, Ben-Aderet N. Huge mesenteric mucinous cystadenoma in normal pregnancy. Obstet Gynecol 1988;71(6 Pt 2):1030-2. [5.] Buller RE, Holter H, Laros RK Jr, Hanson KH, Abele J. Massive ovarian mucinous cystadenoma of low malignant potential. Obstet Gynecol 1982;59(6 Suppl):112S-6S. [6.] U.S. Preventives Services Task Force. Guide to clinical preventive services: an assessment of the effectiveness of 169 interventions. Baltimore: Williams & Wilkins, 1989:81-4. [7.] Bast RC Jr, Klug TL, St. John E, et al. A radioimmunoassay using a monoclonal antibody to monitor the course of epithelial ovarian cancer. N Engl J Med 1983;309:883-7. [8.] Stenchever MA. Office gynecology. St. Louis: Mosby-Year Book, 1992:430-40. [9.] DiSaia PJ, Creasman WT. Clinical gynecologic oncology. St. Louis: Mosby, 1984:255. [10.] Pernoll ML, Benson RC, eds. Current obstetric and gynecologic diagnosis and treatment. Norwalk, Conn.: Appleton & Lange, 1987:672. [11.] Alvarez RD, Varner RE. Hyperandrogenic state associated with a mucinous cystadenoma. Obstet Gynecol 1987;69(3 Pt 2):507-10. [12.] Garcia-Villanueva M, Badia Figuerola N, Ruiz del Arbol L, Hernandez Ortiz MJ. Zollinger-Ellison syndrome due to a borderline mucinous cystadenoma of the ovary. Obstet Gynecol 1990;75(3 Pt 2):549-52. [13.] Robbins SL, Cotran RS, Kumar V. Pathologic basis of disease. 3d ed. Philadelphia: Saunders, 1984: 1146. [14.] Jones HW 3d, Wentz AC, Burnett LS. Novak's Textbook of gynecology. 11th ed. Baltimore: Williams & Wilkins, 1988:806-7. [15.] Stenback F. Morphology of ovarian mucinous cystadenoma: surface ultrastructure, development and biologic behavior. Int J Gynaecol Obstet 1980;18(3): 157-67. [16.] Chaitin BA, Gershenson DM, Evans HL. Mucinous tumors of the ovary. A clinicopathologic study of 70 cases. Cancer 1985;55:1958-62. [17.] Jensen ML, Nielsen MN. Broad ligament mucinous cystadenoma of borderline malignancy. Histopathology 1990;16:89-91. [18.] Woodruff J. Benign, premalignant, and malignant disorders of the ovaries and oviducts. In: Pernoll ML, Benson RC, eds. Current obstetric and gynecologic diagnosis and treatment. 6th ed. Norwalk, Conn.: Appleton & Lange, 1987:680-2. [19.] Hart WR, Norris HJ. Borderline and malignant mucinous tumors of the ovary. Histologic criteria and clinical behavior. Cancer 1973;31:1031045.

Daneil J. Hein, M.D. is currently in private practice in Smith Center, Kan. Dr. Hein is a graduate of the University of kansas School of Medicine-Wichita, and completed a residency at the Smoky Hill Family Practice Residency in Salina, Kan.

Rick D. Kellerman, M.D. is director of the Smoky Hill Family Practice Residency. Dr. Kellerman is a graduate of the University of Kansas School of Medicine-Wichita and completed a family practice residency at Wesley Family Practice, Wichita. He is a past president of the Kansas Academy of Family Physicians.

Greg Abbott, D.O. is clinical director of Indian Health Services in Holton, Kan. Dr. Abbott is a graduate of the University of Health Sciences, Kansas City, Mo., and completed a family practice residency at the Smoky Hill Family Practice Residency.

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