MDCalc

International Ovarian Tumor Analysis (IOTA) Simple Rules Risk Assessment

Predicts risk of malignancy in adnexal masses using ultrasound features.

This tool provides an estimated risk of malignancy in patients who are undergoing adnexal surgery.

B1 (unilocular cyst)

B2 (solid components present, but <7 mm)

B3 (acoustic shadows)

B4 (smooth multilocular tumor with largest diameter <100 mm)

B5 (no blood flow; color score 1)

M1 (irregular solid tumor)

M2 (ascites)

M3 (at least 4 papillary structures)

M4 (irregular multilocular solid tumor with largest diameter ≥100 mm)

M5 (very strong flow; color score 4)

Ultrasound examination at oncology center

Result:

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Management
  • M features are more closely associated with malignancy while B features are more associated with a benign tumor. 
  • The presence of M features increases the risk of a tumor being malignant while the presence of B features will decrease the risk. 
  • Use as part of presurgical counseling and planning with your patient. Remember to only use this score in patients who are undergoing surgery.

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