Tehran University of Medical Sciences Case Reports in Clinical Practice 2538-2683 1 2 2016 09 24 48 53 EN Mohammadreza Razzaghof Medical Student, Department of Rheumatology, Vali-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran Shafieh Movassaghi Associate Professor, Department of Rheumatology, Vali-Asr Hospital, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Mitra Abbasifard Assistant Professor, Department of Internal Medicine, Ali-ibn Abi Talib Hospital, Rafsanjan University of Medical Sciences, Rafsanjan, Iran Fatemeh Shahbazi Assistant Professor, Department of Biology, Payame Noor University, Tehran, Iran 2015 12 01 2016 02 27 A 38-year-old man came to outpatient clinic complaining of a new-onset pain of his right buttock which has caused him to limp. Since six months ago, the pain had involved in order his cervical spine, ribs, sternum andthoracic spine, and left them deformed. He also had constitutional symptoms and significant weight loss. On physical examination, there was a limited chest expansion, positive Schober’s test, and multiple tender bony bumps along the ribs, costosternal and costochondral junctions. Lab tests showed anemia, elevated ESR, normal level of serum calcium, and creatinine, and 1+ protein in U/A. Serum protein electrophoresis was unexceptional. The imaging of the patient changed the diagnostic path. This article describes a deceptive visage of multiple myeloma presenting itself in the clothing of ankylosing spondylitis. https://crcp.tums.ac.ir/index.php/crcp/article/view/18 https://crcp.tums.ac.ir/index.php/crcp/article/download/18/17