6. Ovarian/Adnexal Pathology

Ovarian Neoplasms

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 pelvic ultrasound gynecologymucinous cystadenoma pelvic ultrasound gynecology
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
bilateral-ovarian-serous-cystadenoma pelvic ultrasound
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
Gynecology cancer malignancy Pelvic Ultrasound serous ovarian cystadenocarcinoma
Serous Cystadenoma
6. Ovarian/Adnexal Pathology

Pelvic Inflammatory Disease (PID)

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.


  • 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)
  • Pelvic free fluid (*hyperlink)
  • Hydrosalpinx (waist sign, beads-on-a-string sign, (cogwheel sign) (*hyperlink)
  • Multicystic ovaries (*hyperlink)
  • Tubo-ovarian abscesses (end-stage) (*hyperlink)
6. Ovarian/Adnexal Pathology

Tubo-ovarian Abscess

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
Tubo-ovarian abscess pelvic ultrasound
Tubo-ovarian abscess; (Radiopaedia)
6. Ovarian/Adnexal Pathology


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.


  • 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
Hydrosalpinx Pelvic Ultrasound Waist Sign
Waist sign (arrows); Transvaginal scan
Hydrosalpinx Pelvic Ultrasound Beads on A String Sign
Beads on a string; Transvaginal scan
6. Ovarian/Adnexal Pathology

Ovarian Torsion

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.


  • 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
ovarian-torsion pelvic ultrasound gynecology Power Doppler
Right ovarian torsion compared to normal left ovary;
ovarian-torsion pelvic ultrasound gynecology Whirlpool Sign
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% sensitiveColor 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.

6. Ovarian/Adnexal Pathology

Ovarian/Adnexal Pathology

Ovarian Cysts

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 Pelvic OB Gynecology Ultrasound - Labeled
Corpus luteum cyst with first trimester pregnancy
Ring-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.


  • Often asymptomatic
  • Possible bloating
  • Possible pelvic/low back pain

Ultrasound findings of Simple Ovarian Cysts:

  • Smooth/thin-walled pockets containing anechoic fluid
  • Lacking internal vascularization
  • Lacking septa
  • 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 pelvic ultrasound
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.


  • 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.

Hemorrhagic Cyst with Fibrin Strands and Cobweb Appearance Pelvic Ultrasound
Cobweb appearance (fibrin strands) of hemorrhagic cyst (Brown et al., 2010)
Hemorrhagic Cyst with Internal Clot Pelvic Ultrasound
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.


  • 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
Dermoid Cyst Teratoma Diffuse Echogenicity Pelvic Ultrasound
Diffuse echogenicity in dermoid cyst
Dermoid Cyst Teratoma Echogenic Meshwork Pelvic Ultrasound
Echogenic meshwork with dots and lines (arrows) in dermoid cyst (dot-dash sign); Transvaginal scan;
Dermoid Cyst Teratoma Diffuse Echogenicity Pelvic Ultrasound
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:

  1. Hyperandrogenism (Hirsutism, Infertility, Acne, Biochemical Tests)
  2. Ovulatory Dysfunction (Oligomenorrhea, Amenorrhea, or Anovulation)
  3. 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).

Polycystic Ovary Morphology - Gynecology Pelvic Ultrasound
Multiple Follicles Consistent with Polycystic Ovary Morphology (Senaldi 2015)