What is the recommended diagnostic workup for a female patient with a suspected ovarian cyst?

Diagnostic Workup for Suspected Ovarian Cyst

Transvaginal ultrasound is the essential first-line examination for any suspected ovarian cyst, combined with transabdominal ultrasound for masses that extend beyond the pelvis, and this imaging alone is sufficient to characterize most cysts without requiring tumor markers or hormonal testing in the initial evaluation. 1, 2, 3

Initial Imaging Strategy

• Perform transvaginal ultrasound as the primary diagnostic test, which correctly identifies 98.7% of benign processes in premenopausal women and allows classification of cysts as simple, complex, or solid 1, 2

• Add color or power Doppler to every pelvic ultrasound examination to differentiate true solid components from debris within cysts and to evaluate vascularity of any solid areas 1, 2

• Include transabdominal ultrasound for large masses that cannot be fully visualized transvaginally or that extend beyond the pelvis 2, 3

• Reserve MRI with contrast for indeterminate cases where ultrasound findings are unclear or equivocal 2

• Do not use CT for characterizing ovarian cysts due to poor soft tissue discrimination compared to ultrasound and MRI 2

Tumor Marker Testing

CA-125 should NOT be measured routinely in all patients with ovarian cysts—it is only indicated when malignancy is suspected based on ultrasound findings or clinical presentation. 1, 2, 3

• CA-125 performs worse than ultrasound alone in distinguishing benign from malignant lesions and should be measured before any surgery or chemotherapy, but not as a first-line diagnostic test 2, 3

• CA-125 is elevated in only ~50% of early-stage (FIGO stage I) ovarian cancers and can be falsely elevated in benign conditions like endometriosis, making it unreliable for initial diagnosis 1

• Measure CEA and CA 19-9 only if mucinous carcinoma is suspected (particularly if CA-125/CEA ratio is <25:1), and consider endoscopy in this scenario to exclude gastrointestinal metastasis 1

• CA-125 can be falsely low in borderline and low-grade malignant tumors, further limiting its utility as a screening tool 2

Risk Stratification Using Ultrasound Features

Apply the IOTA Simple Rules to stratify malignancy risk, which achieves 93% sensitivity and 81% specificity—superior to CA-125 alone and equal to complex logistic regression models 1

Benign Features (B features):

• Unilocular cyst 1
• Solid components <7 mm 1
• Acoustic shadows 1
• Smooth multilocular tumor <100 mm 1
• No blood flow on Doppler 1

Malignant Features (M features):

• Irregular solid tumor 1
• Ascites 1
• At least four papillary structures 1
• Irregular multilocular-solid tumor ≥100 mm 1
• Very strong blood flow 1

Specific Cyst Characterization by Ultrasound

Most functional and benign cysts can be diagnosed by their characteristic ultrasound appearance without biopsy or aspiration:

• Hemorrhagic cysts: Spiderweb-appearing or retracting clot with peripheral vascularity 1
• Endometriomas: Low-level internal echoes, mural echogenic foci, or nonvascular solid attenuating components 1
• Teratomas (dermoid cysts): Echogenic attenuating component or small horizontal interfaces 1
• Hydrosalpinx: Tubular cystic mass with or without folds 1
• Simple cysts: Unilocular with no solid components, septations, or papillary projections—malignancy risk <0.4% 1, 4

Management Algorithm Based on O-RADS Classification

Use the O-RADS system to guide management decisions directly from ultrasound findings: 2, 3

• O-RADS 1-2 (malignancy risk <1%): No follow-up required or surveillance only 2, 3
• O-RADS 3 (risk 1-10%): Manage with general gynecologist, consider ultrasound specialist consultation or MRI 2, 3
• O-RADS 4 (risk 10-50%): Consult gynecologic oncology before any intervention 2, 3
• O-RADS 5 (risk 50-100%): Direct referral to gynecologic oncologist 2, 3

Additional Diagnostic Tests

• Obtain CT of thorax, abdomen, and pelvis only when malignancy is suspected to complete clinical staging and aid surgical planning 1

• Perform cytological assessment of pleural effusion if present in suspected malignancy cases 1

• Detailed history should focus on: symptoms of abdominal/pelvic pain, constipation, urinary frequency, vaginal bleeding, abdominal distension, bloating, early satiety, and family history of ovarian or breast cancer 1

• Clinical examination should assess for: ascites, abdominal masses, pleural effusions, and lymphadenopathy in suspected malignancy 1

Critical Contraindications

Never perform transvaginal aspiration of purely liquid cysts >5 cm in postmenopausal women 2

Never perform fine-needle aspiration for cytological examination of solid or mixed ovarian masses due to the risk of disseminating cancer cells 2

Common Pitfalls to Avoid

• Do not order CA-125 reflexively for all ovarian cysts—ultrasound characteristics are more accurate for initial risk stratification 2, 3

• Do not assume all persistent cysts require surgery—unilocular cysts <10 cm have an extremely low malignancy risk (0.5-0.6% in premenopausal women, <1% in postmenopausal women) and can be safely followed 2, 4

• Do not operate prematurely on simple cysts without appropriate observation—most functional cysts in premenopausal women resolve spontaneously within 8-12 weeks 2, 3

• Do not neglect Doppler evaluation—it is essential for differentiating solid components from debris and assessing vascularity patterns 1, 2

• Remember that the risk of acute complications (torsion, rupture) in benign-appearing lesions is only 0.2-0.4%, so conservative management is safe for appropriate candidates 2