917 - Immune checkpoint inhibitor induced sacroiliitis

Thursday, February 19, 2026

5:00 PM - 6:30 PM AST

Presenting Author(s)

HS

Hunter Soleymani, MD

Resident
Mayo Clinic Rochester
Rochester, Minnesota, United States

Co-Author(s)

CP

Cara Prideaux, MD

Residency Program Director
Mayo Clinic Rochester
Rochester, Minnesota, United States

Submitter(s)

HS

Hunter Soleymani, MD

Mayo Clinic Rochester
Rochester, Minnesota, United States

Case Diagnosis: Immune checkpoint inhibitor (ICI) induced sacroiliitis

Case Description: 32-year-old male with Hodgkin's lymphoma on ICI chemotherapy (Nivolumab for 3 months) presented to clinic with 1 month of progressively worsening pain in the right upper gluteal region. Physical exam revealed difficulty ambulating due to pain, tenderness to palpation over the right sacroiliac joint, and positive FABER test. CRP was significantly elevated at 58.2 mg/L. MRI revealed infectious vs inflammatory sacroiliitis. Given his immunocompromised state, concern for infection, pain refractory to oral pain medications, and significant functional decline he was admitted to the hospital. His ICI was held, and a biopsy/aspiration of the right sacroiliac joint was performed and was ultimately negative for infection. He underwent a right sacroiliac joint corticosteroid injection while hospitalized with significant improvement/near resolution of his pain.

Discussions: ICIs are a revolutionary form of chemotherapy that disrupt cytotoxic T-lymphocyte–associated protein 4, programmed cell death protein 1, and programmed death ligand 1 pathways so that T cells can recognize and attack cancer cells. Due to this, the immune system is “revved up” which can lead to immune-mediated side effects. Arthralgias are common (up to 43%) among patients receiving ICI therapy. Patients with ICI induced arthritis can have a wide range of presentations including large and/or small joint involvement, reactive arthritis, symmetric polyarthritis resembling rheumatoid arthritis, or sacroiliitis. Median time to onset is 38 weeks following initiation of an ICI, but can vary greatly from 1-127 weeks. Other pathologies such as osteoarthritis, crystal arthropathies, and septic arthritis should be ruled out. Inflammatory markers are usually significantly elevated in patients with ICI-induced arthritis. NSAIDs alone are usually not sufficient for treatment, and corticosteroids and disease-modifying antirheumatic drugs might be required.

Conclusions: Physiatrists should be cognizant that ICIs can commonly have musculoskeletal side effects including sacroiliitis among other widely variable musculoskeletal clinical presentations.