Tumors that arise in the seminal vesicles (SVs) as a primary site are rare (Table 5.1). Clinical presentations include pelvic pain and urinary or rectal obstructive symptoms. Some may be asymptomatic, and detected by digital rectal examination and sonography. Needle or open biopsy is required to establish the diagnosis. It may be difficult to ascertain the site of origin when adjacent pelvic organs are involved.