We herein describe the case of a 25-year-old woman who suffered from atypical familial Mediterranean fever for more than a decade. She presented with a periodic fever, abdominal pain and persistent ulcers in the terminal ileum. Colchicine was effective, and familial Mediterranean fever was diagnosed. A genetic study showed a heterozygous E148Q mutation in the MEFV gene. Multiple, recurrent, abscess-like lesions developed asynchronously in the spleen, liver, and a lung. Infliximab was administered when colchicine treatment became ineffective. However, infliximab treatment soon became ineffective, probably because antibodies were generated against it. Therefore, etanercept treatment was started, and the patient showed an immediate response.