Dermatomyositis and cutaneous metastases from breast cancer: simultaneous development and parallel course.

The association between dermatomyositis (DM) and various types of malignancies has been reported in several studies, with an estimated frequency of about 20-25%. Cancer may appear before the onset of DM, concurrently with DM or after its onset. In the present report, the occurrence of typical DM in concomitance with development of skin metastases from previously treated breast cancer is described, suggesting the role of DM as paraneoplastic marker not only in association with the primary tumor but also in case of cutaneous involvement by cancer.