Images of the month: Lower-back pain in a young man with HLA B27 - not always spondyloarthritis!

Presence of human leucocyte antigen (HLA) B27 in a patient with lower-back pain should not be considered synonymous with axial spondyloarthritis. Other causes of back pain should be ruled-out by careful evaluation. Lumbosacral transitional vertebra is a common congenital malformation of spine which frequently leads to mechanical back pain. We present a young man with lower-back pain who had HLA B27. He was labelled with axial spondyloarthritis elsewhere and was given etanercept without benefit. Further evaluation revealed that he had lumbosacral transitional vertebra and spina bifida occulta. No evidence of sacroiliitis was found. Etanercept was stopped and he was started on physiotherapy protocol for transitional vertebra, with which he improved remarkably. This case highlights the need for greater awareness among clinicians about lumbosacral transitional vertebra, a finding which is frequently missed. Presence of HLA B27 can be coincidental, as in our case. © Royal College of Physicians 2020. All rights reserved.