Could Hypo Echoic Septated Cystic Lesion In Uterus Be Malignant?

I recently had an ultrasound for my kidney but they looked at the abdomen as well as my ovaries etc. The report says I have a right adnexa contains 5.8x5.5x5.7 cm hypoechoic, septated cystic lesion. I have had ovarian cysts before but, I have never seen it called a hypoechoic, sepated cyst before. My kidney doctor wants me to follow up with my gynecologist and mentioned it could possibly be malignant. This has me worried. I don t see my doctor for 2 weeks. Can someone explain to me what this means?