Read the HSG by following the dye: dye enters the uterine cavity, then travels into both tubes. Where it stops or pools tells you the diagnosis.
Eliminate the options: A cornual block stops the dye right at the tube origin, so the tube never fills, ruled out here because the tubes are clearly filled. A normal study shows free spill of dye into the pelvis, but this image has NO spill. A bicornuate uterus would show a heart-shaped, two-horned cavity, not the case here.
What is left: both tubes are dilated and club-shaped at the far (fimbrial) end and the dye is trapped inside with no spillage. That trapped, ballooned tube is hydrosalpinx, and since both sides show it, the answer is bilateral hydrosalpinx. Clinical pearl: hydrosalpinx is a common tubal-factor cause of infertility and lowers IVF success, so salpingectomy is often advised before IVF.
Ref: DC Dutta's Textbook of Gynecology, 6th Edition.