Familial Mediterranean Fever without Fever.

Familial Mediterranean fever (FMF) is an autosomal recessive hereditary disease commonly observed around the Mediterranean basin presenting as recurrent febrile episodes. We herein describe a Japanese case of genetically-confirmed FMF, in which fever was lacking during attacks. An otherwise healthy 34-year-old man presented with frequent episodes of abdominal pain, which resolved spontaneously. During the attacks, the patient was afebrile, but the inflammatory marker levels in his blood were increased. Abdominal CT demonstrated enhancement of the jejunal membrane. After the initiation of colchicine therapy, the patient experienced no attacks for more than one year. The diagnosis of FMF was confirmed by a genetic analysis.