Dermatomyositis Complicated by Digital Ischemia and Lung Adenocarcinoma in a Patient with Positive Anti-signal Recognition Particle Antibodies.

A 58-year-old Japanese woman was diagnosed with anti-signal recognition particle (SRP)-positive dermatomyositis associated with Sjögren's syndrome, rheumatoid arthritis and lung adenocarcinoma. She presented with cutaneous lesions, including ulceration of her right middle finger. Tissue specimens obtained from her right deltoid muscle were positive for CD4+ T-cell infiltration and the sarcolemma showed the upregulation of major histocompatibility complex (MHC) class I antigens. The present case suggests that overlapping autoimmune diseases or complications of malignancy may result in an atypical clinical presentations and histological findings in patients with anti-SRP antibody-positive dermatomyositis.