成人型史笛兒氏症為不明原因發燒的鑑別診斷之一，典型表現以高燒、皮疹、關節痛為主；然而此病可以肝功能異常最為初始變化。史笛兒氏症因缺乏適當的實驗室數值在臨床上診斷不易，雖肝功能為此病診斷的次要標準之一，但不易將此症狀與成人型史笛兒氏症相連結。本篇提出一位肝功能異常患者，初始疑似脂肪肝隨後確診成人型史笛兒氏症的案例。藉由此案例進一步了解成人型史笛兒氏症之臨床表現與常見肝功能異常診斷之異同。

Adult-onset Still’s disease (AOSD) is one of the differential diagnoses of fever of unknown origin. The typical manifestations of AOSD include spiking fever, an evanescent skin rash, and arthralgia. However, impairment of liver function may also be the first symptom of AOSD. Due to the lack of appropriate laboratory examination, the diagnosis of AOSD is difficult, and with abnormal liver function being one of the minor criteria of AOSD, it is difficult to correlate with the disease. We describe the case of a patient with abnormal liver function who was first diagnosed with nonalcoholic fatty liver and finally with AOSD. Through this case, we could learn a lesson from the manifestations of AOSD, which are different from other common causes of impaired liver function.