A 24-year-old woman who had given birth to her second child 6 months prior to presentation arrived for an outpatient examination with a complaint of pain in the lower back and buttocks. The pain had initially started in the lower back but had moved to the iliac and sacroiliac areas and buttocks. These areas were tender on a physical examination. Clenching the anus intensified the pain, and the pain prevented the patient from sitting in a chair. Her body temperature was 36.6℃, and her blood pressure was 110/58 mmHg. Blood tests revealed a white blood cell count of 7,100/μL and a C-reactive protein (CRP) level of 0.04 mg/dL. Computed tomography (CT) of the abdomen without contrast revealed sclerosis, predominantly in the ilium adjacent to both sacroiliac joints. No joint irregularity, erosions, or loss of joint space was observed (Picture 1). T1- (Picture 2a) and T2-weighted magnetic resonance imaging (MRI) (Picture 2b) also showed hardening of the sacroiliac joints. No signs of inflammatory pathology (e.g. synovitis, osteitis) were observed on MRI. Based on the imaging findings, we diagnosed her with osteitis condensans ilii. We prescribed her rest and non-steroidal anti-inflammatory drugs. Osteitis condensans ilii is a benign disease wherein the lower segment of the ilium undergoes localized bone hardening at its attachment to the sacroiliac joint. Typically, joint irregularity, erosions, or loss of joint space are not observed in osteitis condensans ilii (1). CT and MRI are useful for distinguishing osteitis condensans ilii from metastatic bone tumors and ankylosing spondylitis.
Picture 1.
Picture 2.
The authors state that they have no Conflict of Interest (COI).
References
- 1.Cidem M, Capkin E, Karkucak M, Karaca A. Osteitis condensans ilii in differential diagnosis of patients with chronic low back pain: a review of the literature. Mod Rheumatol 22: 467-469, 2012. [DOI] [PubMed] [Google Scholar]