Should an ultrasound be performed if a cystic structure is seen on the left adnexa?

Should Ultrasound Be Performed for a Cystic Structure in the Left Adnexa?

Yes, transvaginal ultrasound combined with transabdominal ultrasound is the essential first-line imaging modality for evaluating any adnexal cystic structure, regardless of how it was initially detected. 1, 2

Initial Imaging Approach

Transvaginal ultrasound with color Doppler is the most appropriate and necessary imaging study for characterizing any adnexal cystic structure. 1, 2 This approach allows for:

• Definitive characterization of the cyst as simple, hemorrhagic, complex, or solid 1
• Assessment of vascularity using color or power Doppler to evaluate any solid components 1, 2
• Risk stratification to determine whether the lesion is benign, indeterminate, or concerning for malignancy 1

The transabdominal component provides complementary visualization, particularly for larger masses that may extend beyond the transvaginal field of view. 1, 2

Why Ultrasound Is Critical

Establishes Benignity in Most Cases

Simple cysts are benign in 98.7% of premenopausal women, making ultrasound characterization essential to avoid unnecessary intervention. 1 The sonographic features determine the entire management pathway:

• Simple cysts (anechoic, unilocular, smooth thin wall) have a malignancy risk of <0.4% 1
• Hemorrhagic cysts show characteristic spiderweb-appearing or retracting clot with peripheral vascularity 1
• Specific benign lesions like endometriomas, dermoids, and hydrosalpinges have diagnostic ultrasound features 1

Guides Management Decisions

The ultrasound findings directly determine whether the patient needs:

• No follow-up (simple cysts ≤3 cm in premenopausal women, hemorrhagic cysts ≤5 cm) 2, 3
• Short-term follow-up (hemorrhagic cysts 5-10 cm require repeat ultrasound in 8-12 weeks) 2
• Advanced imaging with MRI (indeterminate masses after ultrasound evaluation) 1
• Gynecologic oncology referral (masses with concerning features for malignancy) 2

Prevents Unnecessary Surgery

Surgical exploration of benign lesions carries complication rates of 2-15%, making accurate preoperative characterization crucial. 2 Ultrasound can correctly identify 95% of dermoid tumors, 80% of endometriomas, and 71% of simple cysts, preventing unnecessary surgical intervention. 1

Key Ultrasound Features to Assess

The sonographer must evaluate:

• Cyst complexity: Simple (anechoic, unilocular) vs. complex (septations, debris, solid components) 1
• Wall characteristics: Smooth and thin vs. thick or irregular 1
• Septations: Thin (<3 mm) vs. thick, single vs. multiple 1
• Solid components: Absence vs. presence of mural nodules or papillary projections 1
• Vascularity: Peripheral flow (benign) vs. central or solid component flow (concerning) 1, 2
• Size: Diameter measurement for follow-up thresholds 2, 3

Common Pitfalls to Avoid

• Do not assume all adnexal cysts require surgery—most are benign and many resolve spontaneously, particularly in premenopausal women 1
• Do not mistake endosalpingeal folds in hydrosalpinx for solid components, which could lead to misclassification as malignant 2
• Do not confuse pedunculated leiomyomas with ovarian masses—careful identification of normal ovaries and blood supply from uterine vessels prevents this error 1
• Do not skip Doppler evaluation—vascularity patterns are essential for risk stratification 1, 2

When Ultrasound Is Insufficient

Up to 22-24% of adnexal masses remain indeterminate after initial ultrasound. 1 In these cases:

• MRI without and with IV contrast is the next appropriate imaging modality, with >90% accuracy for diagnosing malignancy 1
• CT is not recommended for characterizing indeterminate adnexal masses, as MRI is superior for this purpose 1
• PET/CT cannot reliably differentiate benign from malignant adnexal lesions and is not indicated 1