RT Journal Article SR Electronic T1 An Unusual Cause of Lower Back Pain JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP 2556 OP 2556 DO 10.3899/jrheum.090498 VO 36 IS 11 A1 OLGA PETRYNA A1 PETROS EFTHIMIOU YR 2009 UL http://www.jrheum.org/content/36/11/2556.abstract AB