Anti-alanyl tRNA positive antisynthase syndrome with Kaposi sarcoma.

We report a rare case of antisynthase syndrome (ASS) complicated with Kaposi sarcoma, analyze its clinical characteristics, and review the literature on the topic. An 80-year-old male patient developed fever, cough, and shortness of breath. Lung high-resolution computed tomography showed nonspecific interstitial pneumonia in both lungs, and myositis antibody examination showed strongly positive anti-alanyl tRNA synthase (PL-12) antibodies. Based on these findings, the patient was diagnosed with ASS. After full-dose glucocorticoid treatment, the symptoms of fever and cough were relieved, but skin thickening and pigmentation in both feet were observed. We confirmed Kaposi sarcoma through skin pathology and immunohistochemical examination of the bottom of the patient's feet, and the patient was transferred to a cancer hospital for radiotherapy. ASS presents with some skin changes that might lead to misdiagnosis. ASS complicated with Kaposi sarcoma is rare, and to our knowledge, this is the first case reported in China.