Welcome to the community. The "avascular anechoic" would make me think it is a fluid-filled functional cyst that is a normal part of the menstrual cycle. However, sometimes functional cysts can hang around longer than normal and get larger but most do resolve on their own in 2 to 3 cycles. I don't know if "tubular" refers to the shape or that it is in the Fallopian tube. Please get clarification from your doctor. Let us know what you find out.
what is Avascular Anechoic Tubular convoluted cystic structure
sunshine9402,
It only means, there is a cyst.