Cat-scratch disease occurs after a scratch from a cat infected with Bartonella henselae. We report a 64-year-old man with cat-scratch disease who had swollen lymph nodes. Consequently, metastasis of a malignant tumor was suspected as the most likely cause in the differential diagnosis. Therefore, the diagnosis was delayed and several diagnostic examinations were performed. Although diagnosis was difficult in this case, an accurate diagnosis was achieved by taking a detailed medical history, including questioning about pet ownership, and by carefully examining the lower limbs including the femoral region. These steps are important to diagnose cat-scratch disease.