SSc Calcinosis — SCE Rheumatology MCQ

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ModerateSystemic SclerosisSSc CalcinosisSCE Rheumatology

A 40-year-old woman with limited cutaneous systemic sclerosis develops recurrent painful firm nodules in the fingertip pulps. One lesion ulcerates and extrudes white chalk-like material. Serum adjusted calcium, phosphate and urate concentrations are normal. Plain radiography shows multiple discrete subcutaneous and periarticular calcific deposits without bone destruction. Which diagnosis best explains these lesions?

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Correct answer: D — Calcinosis cutis

The diagnosis is calcinosis cutis, a manifestation particularly associated with established limited cutaneous systemic sclerosis. It represents dystrophic deposition of insoluble calcium salts, predominantly hydroxyapatite, in damaged skin and subcutaneous tissues despite normal circulating calcium and phosphate. Fingertip lesions can be painful, ulcerate and discharge chalk-like material; plain radiography demonstrates soft-tissue calcification. Ischaemic digital ulcers are tissue-loss lesions and do not themselves produce discrete calcific deposits. Gouty tophi may discharge white material, but normal urate does not absolutely exclude gout; the systemic-sclerosis context and radiographic calcinosis are more characteristic. Osteomyelitis would usually cause destructive or inflammatory bone changes. Tendon xanthomata are lipid-laden nodules along tendons and are not radiopaque calcium deposits.

Reference: Avanoglu-Guler A et al. Calcinosis in systemic sclerosis: An update on pathogenesis, related complications, and management. Seminars in Arthritis and Rheumatism. 2024;66:152431. https://pubmed.ncbi.nlm.nih.gov/38537324/