Dilatation of the fallopian tube with fluid, seen as an anechoic tubular adnexal mass, is known as what?

• A. Hydrosalpinx
• B. Salpingitis
• C. PID
• D. Paraovarian cyst

Answer: (A)

Dilatation of the fallopian tube with fluid appears on ultrasound as a long, anechoic tubular structure in the adnexa that may extend from the uterus toward the ovary. This image represents a tube that has become obstructed distally, allowing clear serous fluid to accumulate and distend the tube. The walls are typically thin, and the lumen is dark because the fluid is anechoic; sometimes folds or incomplete septations can give a subtle internal texture.

This finding is best described as a hydrosalpinx, which is specifically the fluid-filled dilation of the fallopian tube. It commonly results from prior pelvic inflammatory disease or tubal obstruction and differs from other adnexal entities. A paraovarian cyst, for example, is a simple cyst adjacent to the ovary but separate from it, often with the normal ovary visualized separately. Salpingitis or PID refers to infection of the tube and surrounding tissues and may show thickened walls or debris rather than a straightforward, anechoic tubular dilation. So the key feature here is the dilated, fluid-filled fallopian tube, i.e., hydrosalpinx.