Signs of Malignancy of pelvic tumors:

Because most pelvic masses are discovered, or initially evaluated, by US, every effort should be made to assess the risk of malignancy (13,14). Transvaginal US aids substantially in the evaluation. The following signs correlate with an increased risk of malignancy (15):

• Solid consistency: the more solid tissue present, the greater the risk of malignancy. Solid tissue includes thick walls, thick septations, papillary projections, and solid tumor mass (Fig. 37.16). Unilocular cysts or cysts with thin septations are likely to be benign. Thick-walled, multilocular masses with solid nodules are likely to be malignant. Echogenic solid masses, or portions of masses, that transmit sound poorly are likely to be malignant.
• Size greater than 10 cm correlates with a 64% risk of malignancy in postmenopausal women. Masses under 5 cm are more likely to be benign.
• Color flow US demonstration of blood vessels within papillary projections is evidence of neoplasm and provides differentiation from avascular blood clots adherent to the cyst wall. Vascularized papillary projections are more common with malignant neoplasms.
• Color flow US demonstration of blood vessels within septations is strong evidence of neoplasm. Hemorrhagic functional cysts may be complex in appearance

  
  

  
  but lack internal vascularity. Blood flow in the wall of cystic masses is commonly seen with both benign and malignant lesions.