RESUMEN
Intravesical instillation of BCG(Calmette-Guerin Bacillus) is the most widely used treatment of superficial transitional cell carcinoma of the bladder. While the exact mechanisms are not yet known, it is assumed that the recognition of tumor antigen is enhanced by immunologic response of the urothelium of mycobacterium. Various complications have been reported after BCG treatment and arthritis is observed in 0.5 to% of treated patients. This from of arthritis may be attributed to an antigen of mycobacterium sharing a cross reactive epitope with an antigen in articular cartilage. A 40-year-old male had transurethral resection and intravesical instillation of BCG for transitional cell carcinoma of bladder. Within few days of the fourth instillation, he developed arthritis on right knee and right metatarsal joint. Laboratory findings showed nonspecific inflammatory sign, positive HLA B27, negative rheumatoid facor and negative antinuclear antibody. The joint effusion was aseptic. He was treated with nonsteroidal antiinflammatory drugs (indomethacin 200rag/day) with resolution of arthritis symptom. We report a patient who developed an inflammatory oligoarthritis following intravesica] instillation of BCG for the treatment oof bladder cancer.