• Sonographic characterization of adnexal/ovarian masses
• Triaging surgical referrals (general gynecology vs. gynecologic oncology)
• Standardizing global ultrasound terminology regarding ovarian cysts

• B1: Unilocular
• B2: Presence of solid components, but largest is < 7 mm
• B3: Presence of acoustic shadows (classic for dermoids)
• B4: Smooth multilocular tumor with largest diameter < 100 mm
• B5: No blood flow on Doppler (Color Score 1)

• M1: Irregular solid tumor
• M2: Presence of ascites
• M3: At least 4 papillary structures
• M4: Irregular multilocular solid tumor with largest diameter ≥ 100 mm
• M5: Very strong blood flow on Doppler (Color Score 4)

• Rule 1 (Benign): Must have at least one B-feature AND zero M-features.
• Rule 2 (Malignant): Must have at least one M-feature AND zero B-features.
• Rule 3 (Inconclusive): If it has both B and M features, or NEITHER, the rules do not apply.

• The Simple Rules are highly accurate (~90-95%) but only applicable to about 76% of all adnexal masses.
• For the ~24% that are inconclusive, you MUST defer to an expert ultrasound examiner, an MRI, or apply advanced mathematical models (like IOTA ADNEX).

• Benign: Safe for conservative management, surveillance, or cystectomy/oophorectomy by a general gynecologist depending on symptoms.
• Malignant: Absolute requirement for referral to a trained Gynecologic Oncologist. Attempting surgery by a generalist risks capsule rupture, upgrading the staging and ruining survival odds.
• Inconclusive: Escalate diagnostic imaging (Pelvic MRI with contrast) or utilize the continuous ADNEX model.

The International Ovarian Tumor Analysis (IOTA) consortium revolutionized ultrasound. Rather than relying on tumor markers like CA-125 (which has catastrophic false positive rates in premenopausal women due to endometriosis), they forced objective morphology to dictate risk.