Point-of-care ultrasound can be helpful in the differentiation of the three primary types of ovarian neoplasms: mucinous cystadenoma, serous cystadenoma, and cystadenocarcinoma.
Mucinous Cystadenoma
These types of tumors are the most common type of benign ovarian neoplasm. Patients may appear “gravid” if the mass has grown extensively into the abdomen.
On ultrasound, you can expect to see a cystic mass filled with mucinous material (several small, low-level internal echoes).
Mucinous cystadenoma
Serous Cystadenoma
These tumors are a less common type of benign ovarian neoplasm.
Ultrasound findings include a cystic mass with:
Several thin septations that undulate with transducer palpation.
Few/no internal echoes
Serous cystadenoma
Serous Cystadenocarcinoma
These tumors are malignant and appear on ultrasound as cystic masses with:
Thick septa
Mural nodularity
Solid tissue with internal vascularization
Another clue pointing toward malignancy is the presence of ascites, which is generally absent in benign conditions
Pelvic Inflammatory Disease (PID) is the result of an ascending spread of infection within the pelvis due to a causative organism (most commonly polymicrobial but also due to Chlamydia trachomatis or Neisseria gonorrhoeae infection). The condition is characterized by periovarian inflammation and is most common in women of reproductive age.
Presentation:
Cervical motion tenderness
Pelvic pain
Vaginal discharge
Fever
Uterine/adnexal tenderness
Leukocytosis
Elevated inflammatory markers
Ultrasound findings of Pelvic Inflammatory Disease (PID):
Though PID is clinically diagnosed, ultrasound imaging is the first-line radiologic evaluation method of choice for PID and may be used to appreciate the following:
Adnexal mass with heterogenous echogenicity (often bilateral)
A tubo-ovarian abscess is a pus-filled mass originating in the uterine tube and often extending to involve the ovary. It is a late complication of pelvic inflammatory disease.
The abscess represents a retrograde spread of pelvic or abdominal infection/inflammation and requires prompt identification and treatment to prevent abscess rupture leading to septic shock.
Patient presentation may include the following:
Acute onset pelvic/lower abdominal pain
Cervical motion tenderness
Palpable pelvic mass
Fever
High inflammatory markers
Leukocytosis
Vaginal discharge
Previous history of STI or PID
Ultrasound Findings of Tubo-ovarian Abscess:
Diagnosis by ultrasound imaging may be difficult due to the varied appearances of tubo-ovarian abscesses. However, some frequently seen ultrasound findings include:
Adnexal mass: septated, irregular/thick walls, variable internal echogenicity, possible solid areas
Ovary with ill-defined borders (mass obscures both ovary and fallopian tubes)
Hydrosalpinx is the abnormal accumulation of fluid in the fallopian tubes causing tubal swelling. Common underlying causes of hydrosalpinx include Pelvic Inflammatory Disease, Endometriosis, tubal obstructions/ligations, adhesions, and complications of hysterectomy.
Presentation:
Chronic pelvic pain
Infertility
Possibly asymptomatic
Ultrasound Findings of Hydrosalpinx:
While fallopian tubes are not normally visible on ultrasound, the dilated uterine tubes of hydrosalpinx can be visualized by the following characteristics on ultrasound imaging:
Tubular shaped cystic mass discontinuous with the ipsilateral ovary
Waist sign – indentations on both sides of the tubular mass
Thin wall
Beads-on-a-String sign – cross-sectional view with incomplete septations associated with chronic pelvic inflammation
Cogwheel sign – cross-sectional view with thickened longitudinal folds of the uterine tubes associated with acute pelvic inflammation
Waist sign (arrows); Transvaginal scanBeads on a string; Transvaginal scan
Ovarian Torsion is a gynecologic emergency in which the ovary has twisted on its ligaments and blood supply. Rotation of the ovary leads to compression of arteries, veins, and lymphatics causing congestion, ovarian edema, and potentially infarction if untreated.
Presentation:
Acute pelvic or lower abdominal pain
Tenderness upon palpation with the transvaginal transducer
Nausea/vomiting
Leukocytosis
Ultrasound Findings of Ovarian Torsion:
Decreased power and/or color Doppler flow of veins and arteries*
Unilaterally enlarged/edematous ovary (>4 cm)
Possible midline position of ovary
String-of-Pearls sign – several peripheral follicles due to central lymphatic congestion
Whirlpool sign – wrapping of vessels around central axis of the pedicle shown with Doppler flow
Free pelvic fluid
Ovarian mass
Right ovarian torsion compared to normal left ovary;Whirlpool sign;
*The sensitivity and specificity for ultrasound diagnosis of ovarian torsion are 72.1% and 99.6%, respectively (Rostamzadeh 2014). Because sonography is not 100% sensitive, Color Doppler ultrasound findings may be normal (blood flow maintained) despite the presence of ovarian torsion. This is due to the dual blood supply of the ovaries from both the ovarian and uterine arteries.
Therefore ovarian torsion is considered a clinical diagnosis and emergent gynecology consult should still be obtained if you have a high clinical suspicion despite a normal-appearing ultrasound.
Ovarian cysts are generally benign and show up on ultrasound in a variety of ways depending on their subtype. A few of the most common types are described below.
Corpus Luteum Cysts
Corpus Luteum Cysts are a normal part of the menstrual cycle and can enlarge further during pregnancy. These cysts are not usually associated with any significant symptoms unless they become hemorrhagic.
Ultrasound findings of Corpus Luteum Cysts:
Fluid-filled mass with thick, crenulated (shallowly scalloped, notched) wall
Internal echoes present
No internal vascularization
Possible extensive vascularization of corpus luteum wall on color Doppler – “Ring of Fire Sign” (this sign can also be seen in ectopic pregnancy)
Usually < 3 cm
Corpus luteum cyst with first trimester pregnancyRing-of-fire sign; Transvaginal Color Doppler Scan
Simple Ovarian Cysts
Simple cysts are fluid-filled sacs in the ovary thought to be caused by hormonal imbalances. The majority of simple cysts are benign but should be followed consistently to monitor for changes.
Exhibiting posterior acoustic enhancement (increased echogenicity posterior to the cyst)
Should be <5cm for premenopausal and <3cm for postmenopausal patients (if larger than followup may be warranted) – (Andreotti 2019)
Simple ovarian cyst; Transvaginal sagittal scan
Ruptured/Hemorrhagic Cysts
Hemorrhagic cysts are usually seen in premenopausal women and are typically the result of bleeding into an ovarian cyst, follicle, or corpus luteum cyst.
Presentation:
Acute pelvic, flank, or abdominal pain
Pelvic mass
Possibly asymptomatic
Ultrasound findings of Hemorrhagic Cysts:
Internal echoes with lacy/cobweb appearance (due to fibrin strands)
Clot with irregular borders and no Doppler flow*
Lack of internal vascularization
Thin wall
Posterior acoustic enhancement
*These characteristics can help differentiate between a hemorrhagic cyst and malignant nodule, which typically has internal vascular flow and clots with more rounded edges.
Cobweb appearance (fibrin strands) of hemorrhagic cyst (Brown et al., 2010)Hemorrhagic cyst with internal clot
Hemorrhage cysts generally resolve spontaneously within 8 weeks. Postmenopausal women with cysts > 5 cm should be re-evaluated about 8 weeks after exam to ensure decreased cyst size.
The major complication associated with hemorrhagic cysts is rupture into the peritoneum resulting in symptoms similar to ectopic pregnancy (pain/tenderness on the affected side, nausea/vomiting, etc.).
Dermoid Cysts
Dermoid cysts (also called mature cystic teratomas) are the most common type of benign ovarian neoplasm. They are composed of at least 2 of the 3 fetal tissue layers (endoderm, mesoderm, ectoderm) and can therefore contain a variety of tissue types including thyroid tissue, cartilage, hair, skin, and bone.
Presentation:
Typically asymptomatic (often found incidentally or when associated with ovarian torsion)
Possible symptoms related to pressure on surrounding organs
Ultrasound Findings of Dermoid Cysts:
Due to the variety of tissue types that make up dermoid cysts, they can have several unique appearances on ultrasound imaging. The presence of two or more of the following findings is suggestive of dermoid cysts:
Diffuse echogenicity with posterior acoustic enhancement (increased echogenicity posterior to the cyst) – sebaceous tissue and hair; calcified bone or teeth
Echogenic mesh of lines and dots (“dot-dash sign”) due to the presence of hair.
Floating echoic fat globules
Fluid-fluid level – liquids of differing viscosities
Diffuse echogenicity in dermoid cyst Echogenic meshwork with dots and lines (arrows) in dermoid cyst (dot-dash sign); Transvaginal scan; Floating fat globules in dermoid cyst;
Complications of dermoid cysts include conversion into a malignant tumor, ovarian torsion, hyperthyroidism (if ectopic germ cell tissue is of thyroid gland origin), and cystic rupture.
Polycystic Ovary Syndrome (PCOS)
Polycystic Ovary Syndrome (PCOS) is characterized by at least 2 out of 3 of the following criteria:
Ovulatory Dysfunction (Oligomenorrhea, Amenorrhea, or Anovulation)
Polycystic Ovary Morphology (PCOM) on Ultrasound
One or two ovaries that is >10 mL (volume = 0.5 × length × height × width)
And/or: Large number of follicles (>12) measuring 2-9 mm in either ovary.
The title, polycystic ovary syndrome, is a bit of a misnomer because a polycystic ovary does not contain several cysts (>3 cm) but rather many follicles (< 3cm).
Multiple Follicles Consistent with Polycystic Ovary Morphology (Senaldi 2015)
