A 42-year-old man presents with progressive dyspnea and skin thickening proximal to the elbows involving the trunk. High resolution CT shows bilateral interstitial lung fibrosis. Which autoantibody is most closely associated with this presentation?
- A Anti-centromere antibody
- B Anti-U1 RNP antibody
- C Anti-topoisomerase I (Scl-70) antibody ✓
- D Anti-mitochondrial antibody
Correct answer: C. Anti-topoisomerase I (Scl-70) antibody
Explanation
Diffuse cutaneous systemic sclerosis involving truncal and proximal limb skin correlates strongly with anti-topoisomerase I (Scl-70) antibodies, which also associate with interstitial lung disease and poor prognosis. Anti-centromere defines limited scleroderma (CREST), typically with distal skin involvement and pulmonary hypertension rather than fibrotic ILD. Anti-U1 RNP suggests mixed connective tissue disease, and anti-mitochondrial antibody marks primary biliary cholangitis.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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