Abstract We report a case of possible Behcet's disease (BD) preceded by arthropathy for 5 years. A 29-year-old man experienced right knee swelling and pain since April 1999. Thorough examinations were performed, yet a diagnosis was not established. In December 2004 he experienced recurrent aphtha, following folliculitis-like skin lesions. A human leukocyte antigen examination revealed a positive B51 allele and his illness was diagnosed as possible Behcet disease. Colchicine was administered and his symptoms were ameliorated.