Klippel-Feil syndrome misdiagnosed as spondyloarthropathy: case-based review.

Spondyloarthropathy refers to any joint disease of the vertebral column, but the term is mainly used for a specific group of disorders called seronegative spondyloarthropathies (SpAs). The axial skeletal involvement, peripheral and extra-articular manifestations and an association with the major histocompatibility complex class I human leukocyte antigen-B27 (HLA B27) are commonly shared features of SpAs. Klippel-Feil syndrome (KFS) is a rare congenital disorder characterized by the fusion of one or more cervical vertebrae, accompanied by various skeletal and extra-skeletal anomalies. We report a case of an adult male patient with HLA B27 positivity presenting with chronic cervical spine pain accompanied by morning stiffness and periodic night pain, with radiologically confirmed ankylosis and fusion of several cervical segments. His medical history included urogenital abnormalities operated in childhood and mild mitral prolapse. Initially suspected diagnosis of an early axial form of SpA was rejected after thorough workup. Instead, the nature of vertebral defects along with the past medical history of urogenital and cardiac abnormalities pointed towards the diagnosis of KFS. HLA B27 presence can be a confounder in patients presenting with spinal pain and that is why the differential diagnosis of CSD-s and SpA can be challenging in some patients.