Related Experiment Video
Updated: Aug 6, 2026
Detection of Anti-MDA5 Autoantibodies Using HeLa Cells and Immunocytochemistry with Light Microscopy
Published on: October 31, 2025
Clinical Characteristics and Malignancy Prevalence in Idiopathic Inflammatory Myopathies: A Single-Center Study from
Hanan H AlMalki1,2, Mohammed M Alomair1, Muhammed A Alkhairi1
1Department of Medicine, Rheumatology Unit, Aseer Central Hospital, Abha, Saudi Arabia.
Purpose:
To describe the clinical features of patients with idiopathic inflammatory myopathies (IIM) and report the prevalence of malignancy among them within a single-center cohort in southwestern Saudi Arabia.
Patients And Methods:
We conducted a retrospective study at Aseer Central Hospital, reviewing records of patients diagnosed with IIM according to the ACR/EULAR 2017 classification criteria over a five-year period (January 2021-December 2025). Demographic, clinical, laboratory, and treatment data were collected and analyzed using appropriate statistical tests.
Results:
Twenty-nine patients were included (75.9% female; mean age 41.9 years). Dermatomyositis (DM, 12/29, 41.4%) predominated, followed by polymyositis (PM, 10/29, 34.5%) and antisynthetase syndrome (ASA, 7/29, 24.1%). Skin manifestations were observed in all DM patients, with isolated involvement in one ASA patient (100% DM vs 0.0% PM vs 14.3% ASA; p < 0.001). Creatine phosphokinase (CPK) was significantly higher in PM and ASA versus DM (medians 4884 and 6334 vs 316 U/L; p = 0.005). Interstitial lung disease (ILD) was most prevalent in ASA (71.4% vs 20.0% PM vs 16.7% DM; p = 0.029). Two females with DM aged ≥40 years developed malignancy (ovarian and breast; 2/29, 6.9%). Anti-Jo1 antibodies were present in 7 of 27 tested patients (25.9%), and were significantly associated with ILD (71.4% vs 20.0%, p = 0.023). No malignancy occurred in patients with ILD or anti-Jo1 positivity. Full muscle strength recovery was achieved in 26 of 29 patients (89.7%), though 10 of 29 patients (34.5%) required escalation to intravenous immunoglobulin and/or rituximab for refractory disease.
Conclusion:
Malignancy prevalence (2/29 patients, 6.9%) aligns with recent Saudi data but is lower than that reported in East Asian and many Western reports. In this study, cancer occurred exclusively in DM patients aged ≥ 40 years, lacking ILD or anti-Jo1 antibodies, consistent with established risk patterns. These findings support a clinically guided approach to cancer screening, particularly in patients with DM.