Presence of anti-transcriptional intermediary factor-1 gamma antibodies in a dermatomyositis patient with retroperitoneal cancer of unknown primary site.

A 71-year-old woman with dermatomyositis (DM) received glucocorticoid steroid (GCS) and tacrolimus treatment. Relapse of skin symptoms was observed after tapering the GCS dose, and the patient tested positive for anti-transcriptional intermediary factor-1 gamma (TIF1-γ) antibody. Examinations for malignancy were repeatedly performed. However, no obvious findings indicative of a tumour were observed. Two years after, a retroperitoneal tumour was detected and pathologically diagnosed as poorly differentiated adenocarcinoma. The patient developed intestinal and biliary obstruction and eventually died of sepsis. Herein, we report the presence of anti-TIF1-γ antibodies in a DM patient with cancer of unknown primary site.