Case contributed by Heba Abdelmonem
Diagnosis possible


Low back pain

Patient Data

Age: 23 years
Gender: Male

MRI pelvis (sacroiliac joints)


Abnormal narrowing, ankylosis, and bone bridging of the synovial portion of both sacroiliac joints. Abnormal high signal on T1 and T2WI series, with signal loss on fat suppressed images, denotes fatty metaplasia. STIR sequences show no bone marrow edema within either iliac or sacral surfaces of the joint.

Similar changes of fatty metaplasia are demonstrated at the left L5-S1 facet joint.

Modic type II changes of the S1 superior endplate.

Case Discussion

Young male with pelvic pain, MRI revealed ankylosis of both sacroiliac joints with fatty metaplasia of the articulating surfaces. No signs of bone marrow edema to suggest active disease.

These findings are consistent with ankylosing spondylitis in a young male with chronic lower back pain, although a full clinical evaluation is necessary for diagnosis and to exclude other forms of axial spondyloarthritis.

Ankylosing spondylitis has a male predilection.

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