Abstract: The related studies on dermatomyositis/polymyositis were searched in databases, including Pubmed, Embase, China National Knowledge Infrastructure (CNKI) and Wanfang database from inception to February 2020. Two reviewers screened literature and extracted data. The data was analyzed by Stata 14 and the publication bias was evaluated by Egger test. Results: A total of 14 literatures were included, involving 2273 patients, 21 variables. Of 21 variables, 13 were associated with tumors. Of the 13 factors, the skin symptoms included Gottron syndrome, V-rash on chest, eyelid erythema, severe itching and discoloration of skin.

Key words: dermatomyositis, polymyositis, tumor, risk factor, meta analysis