ASHEVILLE, N.C. — Ultrasound can be an important tool in classifying suspicious ovarian masses, said Dr. Angela Gantt, who spoke here at the Southern Obstetric and Gynecologic Seminar.
Thanks to a burgeoning problem with obesity, it has become more difficult to determine which masses may be dangerous by feel alone, said Dr. Gantt, of the department of obstetrics and gynecology at the University of North Carolina at Chapel Hill.
“If you feel something abnormal, ultrasound helps you determine what course to take,” she said. According to Dr. Gantt, 13%–21% of women who have a suspicious mass end up having surgery, so it's important to determine the nature of the mass. Ultrasound can be used to rule out a malignancy because it offers high sensitivity. Unfortunately, it is not very specific.
It takes a skilled technician to properly interpret an exam, but even so, the technology offers many advantages: It is ubiquitous, offers information quickly, and can distinguish physiologic from pathologic processes, said Dr. Gantt.
Among the pearls offered by Dr. Gantt: If an ovary is surrounding a mass, it is probably not a cancer; solid masses should be the subject of more imaging or surgical intervention; a simple cyst of less than 4 cm can be managed conservatively; a larger cyst puts the ovary at risk; pay particular attention to a solid mass in a woman over age 50, as 80% of cancers are diagnosed in this group; and never rule out a pregnancy in women aged 13–65.
The most common finding is a simple cyst, which is almost always benign and includes follicular cysts, corpus luteal cysts, ovarian surface inclusion cysts, and paraovarian/paratubal cysts. On ultrasound, these are generally thin-walled (less than 3 mm), have oval-shaped or circular walls, no solid components, no septations, and no internal vascular activity, said Dr. Gantt. Generally, these cysts are observed. For premenopausal women, if cysts are less than 4 cm, a follow-up ultrasound is not generally recommended; at 4–7 cm, a follow-up scan can be done in 10–12 weeks. Surgical evaluation is recommended in cysts larger than 7 cm.
Recommendations are slightly different for postmenopausal women, she said. Cysts of less than 3 cm should receive a repeat ultrasound in 10–12 weeks and again in 6 months and every year if they are stable. At 3–5 cm, a follow-up scan should be done at 10–12 weeks; if stable, the physician should weigh a follow-up ultrasound or surgical evaluation. Surgery is recommended for cysts larger than 5 cm in these women, she said.
Ultrasound can be an especially good tool for more complex masses, which can be classified with Timor's scoring system, which assigns a numerical score based on the inner wall features, wall thickness, septa, and echogenicity. Often, a peritoneal pseudocyst can mimic complex multicystic ovaries. The pseudocysts are common in patients with a history of pelvic inflammatory disease or abdominal surgery.
Hemorrhagic corpus luteum can be difficult to distinguish from malignancy. Typically, it presents as a spiderweb-like pattern, said Dr. Gantt. With Doppler, it becomes clear there is no vascular activity within the cyst, and the contents tend to morph with any probing. Repeat ultrasounds should be conducted, as the condition tends to resolve within two cycles.
Endometriosis is often confused with hemorrhagic corpus luteum. Ultrasound can be used to support a clinician's diagnosis, but it's not as good at confirming the condition until it is at a later stage, Dr. Gantt said. The test will show a cyst with thickened walls and echogenic foci in the walls, along with no vascular activity.
Similarly, the technology is not as accurate in diagnosing pelvic inflammatory disease in its early stages, she said.
Ultrasound is helpful for distinguishing adnexal myomas, which also can be confused with solid tumors. Doppler can be used to identify vasculature to the uterine cavity.
The most common benign ovarian mass is a mature teratoma. Its size generally makes it symptomatic, though symptoms are variable, said Dr. Gantt. As it gets larger, there is a risk of ovarian torsion. On ultrasound, it may be very dense, so the key is to look for the “tip of the iceberg” sign, which will be hyperechoic with posterior shadowing. It may also show as hyperechoic speckling or as diffuse dots and lines within the cyst.
Finally, malignancies will be solid, though extremely variable, with irregular outlines or walls, and thickened cyst walls and septations of greater than 3 mm. There may be papillary projections into the cyst from the cyst wall. And the vascular pattern and flow—as shown by Doppler—is extremely abnormal and irregular.