Part 3: Ovarian neoplasms
Not all neoplasms represent cancer, and some have overlapping sonographic characteristics. Here's what you need to know to differentiate what is benign from what is malignant.
No doubt about it: Scanning the adnexae is the most challenging task in gynecologic ultrasonography (US). There are many reasons for the difficulty, but probably none more important than the fact that you are expected to reach a conclusion about what you see—or at least narrow the differential diagnosis.
Some ultrasound laboratories try to hedge their bets, sending the referring physician a report that is nothing more than an exhaustive differential diagnosis, similar to what we see in textbooks. Such a list is useless to a referring clinician, who has probably already considered most of the possibilities and involved the lab to help narrow them down. Labs that send such reports are usually trying to protect themselves from litigation—typically involving cases in which ovarian cancer was missed—or attempting to accomplish a “self-referral” by encouraging further imaging.1
The referring physician is not perfect, either. In our practice, we often receive reports like the following terse description:
A complex cyst was seen in the adnexa. Ovarian malignancy cannot be ruled out.
That’s it. No description of the actual sonographic characteristics. No Doppler velocity flow studies. Yet, the few remarks include a mention of malignancy, and the provider often suggests that “additional imaging such as CT and MRI should be considered.”
When we scrutinize the sonographic images upon which these reports are based, we often discover a corpus luteum, cystic teratoma, benign cystadenoma, endometrioma, or, even, a simple cyst.
The need for competency is compelling
Now that gynecologic US has matured as a field in its own right, the referring physician should expect much more from a laboratory’s pelvic scan than a long recitation of potential diagnoses. And the lab should expect more basic information from the referring provider.
That is the primary reason for this four-part series—to help you identify some of the most prevalent adnexal masses, so that you can exclude cases that are no cause for concern, such as a corpus luteum, and refer patients who really do need additional imaging and expertise, providing as much information in the process as you can.
In Part 1 of the series, we introduce you to basic concepts, recommend equipment, and step you through numerous fundamental scans. Part 2 will focus on nonneoplastic ovarian masses, Part 3 on ovarian neoplasms, and Part 4 on tubal entities such as ectopic pregnancy and torsion.
As much as possible, we educate you by providing actual scans that represent real cases, pointing out the elements that should grab your attention. After all, a picture paints a thousand words.
Ultrasound reveals the polycystic nature of a patient’s ovary. The hilus is prominently hyperechoic.
Before we shift our focus to scanning techniques and interpretation of images, we’d like to offer several basic pointers.
Establish, and document, the hormonal milieu. One of the most important requirements of US imaging, particularly during the reproductive years, is determining and documenting the date of the patient’s last menstrual period (LMP). The reason? Physiologic and pathologic processes involving the reproductive organs are driven by the menstrual cycle—or by therapeutic (or pathologic) hormonal stimulation. We mark each scan with the date of the LMP. If the patient is on hormone therapy, we also mark the scan “HT.” We make these marks on the screen in a way that prevents their erasure every time the picture is frozen and unfrozen. This makes it possible for us to look at the scan days, weeks, or even years later and know what day of the cycle it represents. Every finding must be judged in light of the patient’s hormonal status.
Use a transvaginal transducer. It provides a high-resolution view of any pathology. If need be, it can be combined with a trans-abdominal transducer to afford a more deeply penetrating, panoramic view of the pelvis. We use a variety of transducers to achieve depth, color, power Doppler, and three- dimensional (3D) US.