Calcinosis Cutis in a Patient With Systemic Lupus Erythematosus: A Case Report

Systemic lupus erythematosus (SLE) is a systemic, remitting, and relapsing autoimmune disease. It is associated with deficiency of early complement proteins, impaired clearance of immune complexes, and numerous clinical manifestations and morbidities. We report the case of a 40-year-old woman with a known diagnosis of systemic lupus erythematosus (SLE) who presented to the outpatient department with painful skin lesions over the left and right popliteal regions. She also reported generalized body aches, persistent fever that worsened at night, pain in multiple small and large joints, pruritus, hair loss, dry mouth, and right hip swelling for five years. Blood investigations revealed a positive antinuclear antibody (ANA) titer of 1:160 and positive anti-dsDNA antibodies, with normal serum calcium and phosphorus levels and an elevated erythrocyte sedimentation rate (ESR). Radiographs of both knees and the pelvis demonstrated multiple soft tissue calcifications of varying sizes. Histopathological examination revealed dense, massive calcified material in the subcutaneous tissue, confirming a diagnosis of calcinosis cutis. Surgical excision of the lesion was performed, and immunosuppressive agents were administered. However, one month later, the patient re-presented with a persistent infected wound that required antibiotic therapy. She subsequently received further medical treatment and underwent repeat surgical excision. Calcinosis cutis is an exceedingly rare but potentially unfavorable complication of systemic lupus erythematosus, with only a limited number of cases reported in the literature, and it is most often associated with underlying cutaneous pathology. Clinicians must maintain a high index of suspicion to assure early diagnosis and treatment.