Background: Sarcoidosis is a multisystem granulomatous disorder of unknown aetiology with frequent skin involvement.
Objective: To investigate the frequency of 'Borrelia-like' organisms in cutaneous sarcoidosis (CS) by focus-floating microscopy (FFM).
Methods: Retrospective analysis of 38 CS specimens by immunohistochemistry with polyclonal anti-Borrelia antibody and assessment by FFM.
Results: Specimens of 34.2% CS were positive for 'Borrelia-like' organisms by FFM. Usually single spirochetes, rarely pairs or small clusters of bacteria were observed between collagen bundles or at the periphery of granulomas. Polymerase chain reaction (PCR) was performed in addition in 11 cases and was negative in all biopsies. Samples of erythema migrans served as positive controls: 92.3% of 39 samples were positive by FFM, but only 46.6% gave positive results by PCR. Of 61 negative controls only one specimen was falsely positive by immunohistochemistry.
Conclusion: Detection of 'Borrelia-like' organisms by FFM in tissue sections of CS underlines the possibility that such microorganism maybe involved in the pathogenesis of some cases of CS.