Adnexal Mass in First Trimester
Karen Y. Oh, MD
DIFFERENTIAL DIAGNOSIS
Common
Corpus Luteum Cyst
Ovarian Teratoma
Hyperstimulation Syndrome
Theca Lutein Cysts
Endometrioma
Ovarian Neoplasm
Less Common
Pedunculated Fibroid
Paraovarian Cyst
Hydrosalpinx
Rare but Important
Heterotopic Pregnancy
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
Determine if mass is ovarian
Use TV probe to push ovary away from uterus or mass
Concurrent manual compression on low abdomen/pelvis can be helpful
Distinguish paraovarian or adnexal mass from ovarian mass by direct visualization during manipulation
Look for secondary findings
Echogenic free fluid (hemorrhage)
Helpful Clues for Common Diagnoses
Corpus Luteum Cyst
Very commonly identified in first trimester
Often complicated by hemorrhage of varying degrees
Look for typical reticular echoes seen in hemorrhagic cysts
Occasionally hemorrhage will appear homogeneous and simulate solid mass
“Ring of fire” appearance with Doppler imaging
Most resolve by early second trimester
Ovarian Teratoma
Most common ovarian neoplasm in reproductive age group
Echogenic dermoid “plug” often present
Represents keratin
Appearance varies depending on content of teratoma
Cystic/hypoechoic fat or fat fluid level
Echogenic teeth/bones
Linear echogenic hair
Hyperstimulation Syndrome
Bilateral enlarged, cystic ovaries
Ascites ± pleural effusions
Due to increased vascular permeability
History of in vitro fertility treatments
Usually in women undergoing ovulation induction
Usually suspected due to clinical presentation
Abdominal pain
Nausea/vomiting
Oliguria
Electrolyte imbalances
Hypotension
Theca Lutein Cysts
Most often seen in clinical setting of infertility treatments
Rarely present with singleton pregnancy
Enlarged ovaries
Multiple simple cysts
Usually bilateral
Look for abnormal fetus
Gestational trophoblastic disease
Triploid fetus
Fetal hydrops
Endometrioma
Diffuse, homogeneous, low-level echoes
Unilocular cyst
Occasionally multilocular, may mimic malignancy
Through transmission present
Can have fluid-fluid level if multiple ages of blood present
Look for echogenic foci with comet-tail artifact in the wall
Collections of cholesterol
Most often ovarian in location
Can be seen in broad ligament, cul-de-sac, adjacent to bowel
Ovarian Neoplasm
Varying appearances depending on tissue of origin
Solid mass: Sex-chord stromal tumors
Complex cystic: Epithelial ovarian tumors
Suspicious ovarian masses can be further characterized with MR
Helpful Clues for Less Common Diagnoses
Pedunculated Fibroid
Usually hypoechoic to myometrium
Heterogeneous echotexture may be present
Hemorrhage with retracted clot
Cystic degeneration
Calcifications
Use Doppler to look for vascular connection to underlying myometrium
50% of fibroids grow in size in the first 20 weeks of pregnancy
May be painful
Degenerating fibroids
Twisting of pedunculated fibroid on stalk
Paraovarian Cyst
Located in broad ligament
Round or oval mass medial to ovary
Almost always unilocular and anechoic
Infrequently may be multilocular or have minimal debris
Cyst moves separately from ovary with use of vaginal probe
Hydrosalpinx
Thin-walled tubular structure
Anechoic fluid within
If internal debris present, consider hematosalpinx or pyosalpinx if patient is very ill
Look for thin endosalpingeal folds
“Beads on a string” or “cog wheel” appearance
Aids in confirmation that the “mass” is actually hydrosalpinx
Transvaginal ultrasound mandatory for visualization
Helpful Clues for Rare Diagnoses
Heterotopic Pregnancy
Suspect if adnexal mass with history of fertility treatments
10-40% risk of ectopic pregnancy in fertility patients
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