Under the skin: the clinical enigma of calcinosis cutis

Abstract

This article addresses calcinosis cutis, defined as the ectopic deposition of insoluble calcium salts in the dermis and subcutaneous tissue. It can be caused by a variety of mechanisms. It is classified according to etiology as dystrophic (secondary to tissue disruption in the presence of normocalcemia), metastatic (due to alterations in calcium and phosphate metabolism), iatrogenic, and idiopathic. Clinically, it can manifest as asymptomatic subcutaneous nodules or painful ulcerated plaques with calcium exudate, and is particularly complicated in patients with collagen diseases such as systemic sclerosis or juvenile dermatomyositis. We describe the case of a 57-year-old woman with systemic sclerosis who, for the past three months, has presented multiple firm nodules on the anterior aspect of her right knee, without inflammatory signs and with normal calcium and phosphorus levels. The diagnosis, corroborated by clinical and radiographic findings, underscores the importance of a multidisciplinary approach and early recognition to avoid complications and unnecessary procedures.