Tumoral Calcinosis–like Calcification of the Proximal Interphalangeal Joint Mimicking Rheumatoid Arthritis Flare

Localized dystrophic calcification with tumoral calcinosis–like morphology, characterized by periarticular calcium phosphate deposition, may occur in chronic inflammatory diseases despite normal metabolic variables.¹⁻³ A 74-year-old woman with rheumatoid arthritis (RA) in clinical remission taking methotrexate 4 mg/week and prednisolone 4.5 mg/day developed swelling and tenderness of the right fifth proximal interphalangeal (PIP) joint over 4 months, impairing flexion (Figure 1A).