Cat scratch disease diagnosed by polymerase chain reaction in a patient with suspected tuberculous lymphadenitis.

We present a patient diagnosed as having tuberculous lymphadenitis after lymph node biopsy and referred for tuberculous therapy. On review, because of recent cat exposure, she was tested for cat scratch disease (CSD), but serological tests for Bartonella henselae were negative. However, the diagnosis of CSD was confirmed, and tuberculosis excluded, by polymerase chain reaction techniques. This case serves as a reminder that CSD may mimic tuberculosis histologically and that sensitive molecular diagnostic tests are available.