Transvaginal ultrasound shows a 5 cm adnexal mass with a smooth thin wall, anechoic interior, no internal echoes or solid components, and no Doppler flow. The IOTA simple rules classify this as a benign lesion. This corresponds to IOTA B-feature:

• A Multilocular cyst with <10 locules
• B Solid lesion with regular surface
• C Doppler score 1
• D Unilocular cyst — the most common IOTA benign descriptor ✓

Explanation

IOTA (International Ovarian Tumour Analysis) simple rules classify ovarian masses using M (malignant) and B (benign) features. A unilocular cyst (no internal echoes, no solid components, thin smooth wall) is B-feature B1 and the strongest predictor of benignity. This corresponds to a simple ovarian cyst, likely a functional cyst or serous cystadenoma. B2 is multilocular with <10 locules, B3 is solid with smooth surface, B4 is acoustic shadow, B5 is Doppler score 1.

Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.