My assumption is that it was a synovial cyst, it's the same thing I had removed last year, which by the way was my fifth back surgery. synovial fluid lubricates the joints in the back and when they wear out the fluid will leak from the joint and form a cyst called a synovial cyst. If this in fact is what it was this it is indicative of degenerative back issues, which a herniation would not be surprising or uncommon. When I heard last year that he had a cyst removed it made me curios to if it was removed from the surface of the back or if he was cut open.