Primary myxoid solitary fibrous tumor involving the seminal vesicle.

Although focal myxoid change is a well-recognized feature of solitary fibrous tumor (SFT), predominantly myxoid SFT are exceedingly rare. Reported herein is the case of a 65-year-old man with SFT containing abundant myxoid matrix, arising from the capsule of the right seminal vesicle. To the authors' knowledge this is the first myxoid SFT involving the male genito-urinary system. Recognition of the myxoid variant of SFT is crucial, given possible confusion with a variety of myxoid spindle cell neoplasms with different biological potential in the pelvic cavity.