Abstract: Objective To investigate the clinical features of polymyositis and dermatomyositis(PM/DM) with lymphoma. Methods The clinical data, treatment and prognosis ofPM/DM with lymphoma from 2000 to 2015 in Peking Union Medical College Hospital were retrospectively collected and analyzed. Results Ten cases of PM/DM patients complicated with lymphoma were recruited.6 were female and 4 was male. The mean ages of the diagnosis of PM/DM and lymphoma were 44.5 and 44.9 years old respectively. The average disease course from PM/DM to lymphoma was 4.7months. 6 cases were dermatomyositis and 4 cases were polymyositis. 3 cases had pulmonary fibrosis and 2 cases had arthritis. Nocasehad a positive result of anti-Jo-1 antibody. The most frequent symptoms complicated with lymphoma included as following: enlargement of lymph nodes (9 cases), fever (8 cases), splenomegaly (5 cases). Thetop 3 lymphoma biopsy specimenincluded lymph node(4 cases), skin（2 cases）andlocalmass(2 cases).All the 10 patients were diagnosed as non-Hodgkin lymphoma. 4 cases were derived from T cell, 2 cases from B cell, and 4 cases with unknown origin. The clinical staging showed III B (4 cases) and IV B (6 cases). Immunosuppressant agents were given to treat PM/DM. During thefollow-up period, 5 patients died, 4 patients received chemotherapy and 1 patient was lost. Conclusions The coincidence of PM/DM and lymphoma is not rare. The course between PM/DM and lymphoma is short, and the mortality is high, which should arise the attention of clinicians.

Key words: dermatomyositis, polymyositis, lymphoma