Subcutaneous calcinosis in a patient with anti-MDA5 positive dermatomyositis

A 21-year-old male was admitted because of heliotrope rash and proximal muscle weakness for 1 year and progressive shortness of breath for the preceding 2 months. His serum anti-melanoma differentiation-associated gene 5 (MDA5) antibody was positive and was diagnosed as dermatomyositis 1 year ago at the local hospital. He was treated with oral prednisone and intravenous cyclophosphamide 400 mg every 3 weeks for 10 months. His overall condition was stable until 2 months before admission.

Two months before admission, he developed fever and shortness of breath, which was getting worse gradually. Chest Computed Tomography (CT) revealed interstitial lung disease. Therefore, he was treated with an increased dosage of glucocorticoid and intravenous immunoglobulin infusion combined with cyclophosphamide. However, his dyspnea had been getting worse and the subcutaneous tissue in both hips gradually hardened during hospitalization. On physical examination at admission, heliotrope rash was discovered on his bilateral eyelids. His right hip was hard to palpation. His arterial blood partial pressure of oxygen (PO2) was only 48.6 mmHg. Chest CT scan discovered pneumomediastinum. Meanwhile, a pelvic CT scan showed extensive subcutaneous calcinosis in both hips (Figure 1).^{[1, 2]} His shortness of breath gradually improved after being treated with tofacitinib 5 mg twice a day^[3] and intravenous cyclophosphamide 400 mg every 2 weeks, and his prednisone was tapered.

Figure 1

(A) CT cross-section reveals subcutaneous calcinosis of the pelvic wall (arrowheads); (B) CT stereo imaging of subcutaneous calcinosis (arrowheads).

Three months later, chest CT showed interstitial lung disease but pneumomediastinum had disappeared.