Synovial pathology in Behcet's syndrome.

Eight specimens of synovial membrane from 6 patients with 'definite' Behcet's syndrome were available for histological examination. Only the superficial zones of the synovia were affected, all except one being replaced by dense inflamed granulation tissue composed of lymphocytes mingled with macrophages, vascular elements, fibroblasts, and neutrophils. There was a marked plasma cell infiltrate and lymphoid follicle formation in one synovium only, and there was no evidence of infection. Pannus and erosive change were present in the three specimens which included the articular surface, the erosive change being visualised radiologically in two of these. It is suggested that these appearances are characteristic of Behcet's syndrome and should be added to the list of diagnostic criteria.