Abstract
Hyperostosis triangularis ilii, also called osteitis condensans ilii (OCI), is a rare condition, mostly occurring in females, and the etiology is unknown. This disease is a sclerotic disorder associated with iliac fibrosis, a noninflammatory and self-limiting disorder. This condition primarily affects the iliac part of the sacroiliac joints and sometimes the adjoining bones, such as the sacrum, lumbar vertebrae, and iliac bones. It is an incidental finding in many individuals but rarely associated with lower back pain due to sacroiliac joint involvement. It is mainly treated with physical therapy and medications. OCI should be considered a cause of chronic back pain in females not having ankylosing spondylitis or inflammatory arthritis. Herein, a case of osteitis condensans ilii in a 47-year-old female, presenting with the chief complaints of intermittent lower back pain in the midline and on both sacroiliac regions, without any evidence of ankylosing spondylosis and the X-ray of the pelvis and magnetic resonance imaging (MRI) showing features of OCI, is being reported. The case was managed with medications and exercise, and the patient is under regular follow-up.