A 64-year-old woman presented skin lesions on her face, upper extremities and finger
erythema (heliotropism and Gottron's sign). She had weakness in her lower extremities. She was given a diagnosis of
dermatomyositis (DM), because the serum examination showed that a
myositis-specific antibody was positive whereas
Jo-1 antibody was negative. The findings of chest X-ray and computed tomography showed that she had limited
small cell lung cancer, but no
interstitial pneumonia. She was treated with standard
chemotherapy consisting of
cisplatin and
etoposide with accelerated hyperfractionation
radiotherapy. She showed partial response to the treatment, whereas the skin lesions and
muscle weakness deteriorated accompanied with bone marrow suppression due to
chemotherapy. Skin and muscle biopsy were performed and pathological findings showed typical perivasculitis infiltrated with lymphocytes in muscle and skin. With the recovery of bone marrow suppression and partial response due to
chemotherapy, the skin lesions improved and
creatine kinase became normalized. She was given a diagnosis of paraneoplastic DM. Since severe
leukocytopenia paralleled the deterioration of DM, the decrease of peripheral white blood cell counts, especially regulatory T cell counts, may be associated with DM activity.