[Pyogenic sacroiliitis in a patient with HLA B27]. / Sacroiliite piogênica em paciente portador de HLA B27.

The authors report on a patient with bilateral sacroillitis and positive HLA B27 who developed a pyoarthritis in one of the sacro-iliac joints. They comment the diagnostics difficulties in this type of septic arthritis and the association of the histocompatibility antigen B27 with pyogenic sacroiliitis.