Seminal Vesicle Cyst
A seminal vesicle cyst is a fluid-filled sac that forms within or adjacent to one of the seminal vesicles—glands located near the prostate that help produce semen. These cysts are usually benign and may be congenital or acquired due to obstruction, infection, or inflammation. Many are found incidentally on imaging and cause no symptoms, but larger cysts may lead to pelvic discomfort, urinary symptoms, or issues with ejaculation.
What is it?
A seminal vesicle cyst forms when fluid accumulates in or around a seminal vesicle. Congenital cysts may develop due to structural variations such as ejaculatory duct obstruction or associated abnormalities of the kidney and reproductive tract. Acquired cysts may form after infection, inflammation, trauma, or blockage of the ducts that drain the seminal vesicle.
Imaging—especially MRI—helps identify the cyst’s size, shape, and whether it affects nearby structures like the prostate, bladder, or ejaculatory ducts. Transrectal ultrasound may also be used to evaluate cyst contents and assist with drainage when needed.
Important to Know
Most seminal vesicle cysts are harmless and do not require treatment. When symptoms occur, they are usually related to pressure on nearby structures or inflammation. Larger cysts may affect ejaculation or contribute to pelvic discomfort. Treatment depends on symptoms, cyst size, and presence of infection or obstruction.
Red flag symptoms include fever, severe pelvic pain, difficulty urinating, blood in semen or urine, or sudden worsening of symptoms. These signs may indicate infection or significant obstruction and require prompt evaluation.