We report a case of a 39-year-old female with active systemic lupus erythematosus who complained of lethargy and weakness with a moderate renal impairment. Hypercalcemia was confirmed by laboratory examination. Her X-ray revealed significant ectopic calcinosis in subcutaneous tissue of bilateral hands, and Tc-99(m) methylene diphosphonate bone scan revealed a remarkably intense uptake of bilateral lungs. She had no evidence suggestive of other diseases related to hypercalcemia such as hyperparathyroidism and malignancy. She had abnormally high serum parathyroid hormone-related protein (PTHrP) which fell to normal after treatment. Glucocorticoid, cyclophosphamide plus calcitonin and etidronate were administered and the patient improved greatly. Literature review demonstrated that lupus-related hypercalcemia with ectopic calcinosis is a rare complication and increased PTHrP is probably one of the main mechanisms. Lung uptake in bone scan may be a special and reliable clue suggestive of hypercalcemia.
Keywords: Calcinosis; Hypercalcemia; Parathyroid hormone-related protein; Systemic lupus erythematosus.