Clinical History
A 59-year-old female patient with a known diagnosis of dermatomyositis, presents for a follow-up mammogram after right mastectomy for invasive ductal carcinoma 12 years before.
Imaging Findings
Two-view mammography (mediolateral oblique and cranio-caudal views) of the left breast was obtained. These revealed extensive dense coarse calcifications and arterial calcification (Fig. 1 and 2).
The patient underwent breast ultrasonography, which revealed multiple areas of hyperechoic lesions with strong posterior acoustic shadowing in the subcutaneous fat, some of them deeper in the breast, findings that are consistent with calcifications (Fig. 3, 4, 5 and 6).
Discussion
Dermatomyositis is an autoimmune collagen vascular disease of unknown cause, characterised by chronic inflammation and degeneration of striated muscle and skin [1].
It may occur at any age, with two peak age incidences in the age of onset, one at 5–14 years and the other at 45–64 years of life. The disease affects women approximately two to three times more often than men.
It presents as a proximal symmetrical muscle weakness with vasculitis affecting the skin, muscles and internal organs [1, 2].
Patients with dermatomyositis often present with skin disease as one of the initial manifestations. In about 40% of patients with dermatomyositis, the skin disease is the sole manifestation at onset. Muscle disease may occur concomitantly, precede, or follow the skin disease by weeks to years [2].
Calcinosis is a recognised but uncommon cutaneous manifestation, which is unusually seen in adults (more common in children and adolescents). [3, 4] It presents by diffuse cutaneous, subcutaneous and sometimes muscular calcification [5, 4], which can be seen on plain radiographs of the affected area.
Rarely, when it affects the breast, mammography may show extensive bizarre, dystrophic subcutaneous calcifications, which are classified as benign [5, 4].
The mainstay of treatment is systemic steroids and immunosuppressive agents. It has been suggested that calcinosis may be prevented by early aggressive treatment [6].
Breast cancer has been reported to be associated with dermatomyositis and with the added risk of long-term immunosuppressive medication [7, 4]. Therefore, the development of a breast lump requires appropriate investigation [4].
Differential Diagnosis List
Breast calcinosis
Other collagen vascular diseases such as scleroderma or systemic lupus erythematosus causing dystrophic calcifications
Fat necrosis