Motion tenderness. If the to-and-fro movement of the vaginal probe elicits any motion tenderness, it, too, should be documented. It may be a sign of pelvic peritonitis. In such cases, an “ominous appearing” adnexal finding may represent an inflammatory, rather than malignant, mass.
One of the components of extensive evaluation of the adnexae in general and ovaries in particular is color or power Doppler interrogation—or both.
Tumors contain a relatively large number of pathologic blood vessels that lack the muscular layer found in normal blood vessels and, as a result, demonstrate lower resistance to flow. Diastolic flow is high in these vessels, and resistance and pulsatility indices are low.
We also pay attention when these blood vessels have a tortuous appearance, changes in caliber, anastomoses, and vascular lakes.3 The more tortuous the vessels, with multiple inter-vessel connections and dilatations with changing calibers, the greater the risk of malignancy.4 No less important is the presence of a vessel within a “complex” ovarian mass. A centrally located vessel (also called a “lead vessel”) is suspicious for malignancy.5
A gallery of non-neoplastic ovarian masses
Non-neoplastic cysts are, by far, the most common structures of the ovary. They may be functional, as in the case of the follicles, corpus luteum, and theca lutein cysts, or they may be nonfunctional, as in serous cysts and endometriomas. (As we noted in Part 1, do not call the follicles and corpus luteum “cysts” because this designation suggests pathology.)6
FIGURE 2 Simple cyst
This cyst is anechoic and unilocular with thin walls and no papillae.
Functional cysts
Functional cysts, also known as “simple” cysts, may grow as large as 4 to 5 cm in diameter (Figure 2). They are typically unilocular, anechoic, and thin-walled, with no papillae, and almost never malignant. They usually resolve and require no treatment unless rupture or torsion occurs. Except for the corpus luteum, they have no increased blood flow, and need be viewed only by transvaginal ultrasonography (TVS).
The corpus luteum also can be recognized by TVS. It can exhibit any of a variety of internal structures and echo patterns, due to the multitude of shapes of the blood or clot that can be seen within it (Figure 3).
FIGURE 3 Corpus luteum
A–C. Gray-scale, color Doppler, and power Doppler images, respectively, of a typical corpus luteum. B and C show the enveloping vessels, or “ring of fire.” D. A rather typical gray-scale appearance with a mesh-like, linear internal texture. E. A common feature of the corpus luteum is a linear interphase (arrow) between the clot (c) and the liquified serum (s).
The corpus luteum is typically enveloped by blood vessels, visible on color Doppler as what is called a “ring of fire.” It regresses without intervention. In hyperstimulated ovaries, however, more than one may be present; this poses a real diagnostic challenge when ectopic pregnancy is suspected because it is difficult to differentiate the two entities.
Because the corpus luteum can sometimes resemble some types of ovarian tumors on TVS, imaging during the secretory phase of the cycle in a woman of reproductive age is not ideal. Instead, she should be scanned (or rescanned) between days 5 and 9 of the cycle.
FIGURE 4 Hormonally stimulated ovaries
A, B. The right and left ovaries stimulated by follicle-stimulating hormone preparation (arrow points to hilus). C. An ovary stimulated by clomiphene.
Lutein cysts may reach 5 to 10 cm in diameter. They generally have a thick wall, are multilocular, and typically occur after hormonal induction of ovulation (Figure 4). They also can occur in diabetes, molar pregnancy, and hydrops fetalis. We have seen a unilateral theca lutein cyst in a normal pregnancy (Figure 5). No treatment is necessary unless rupture or torsion occurs.
FIGURE 5 Lutein cysts
A–C. The typical “stained glass” appearance of three lutein cysts of the right ovary in a pregnant patient. D. Color Doppler image of the ovary demonstrating high-velocity flow (peak systolic velocity of 20.4 cm/s).
Serous cysts
These cysts can reach 4 cm in diameter, have smooth walls with no papillae, are unilocular, and occur most often during menopause. No pathological blood flow is visible in their walls. Most gynecologists follow them (Figure 6).1,7
FIGURE 6 Serous cyst
A. Right ovary containing the cyst. B. Normal left ovary. C. Power Doppler interrogation showing no particular flow in the walls of a serous cyst.
Endometriomas
After the simple cyst, the endometrioma is the most prevalent ovarian or adnexal cyst (Figure 7). It usually has a thick wall and is filled with homogeneous fluid with low-level echo-genicity. It can reach 10 cm in size, and many are bilateral. It is sometimes called a “chocolate” cyst because of its dark blood content.
