Sporothrix tenosynovitis--differential diagnosis of granulomatous inflammatory disease of the joints.

Sporothrix tenosynovitis is difficult to distinguish from rheumatoid arthritis--the organisms are scarce in biopsy specimens, and both diseases cause a granulomatous synovitis which can affect multiple joints, have associated subcutaneous nodules, similar radiographic findings, and respond to heat and salicylates. This report describes a patient treated for over 2 years as having rheumatoid arthritis. Multiple tenosynovectomy specimens revealed granulomatous synovitis with sterile cultures. Eventually a fungal culture was positive for Sporothrix. This report discusses the histopathologic features of Sporothrix synovitis, and stresses the importance of repeated fungal cultures from patients with granulomatous synovitis unresponsive to steroids.