Utility of Wang needle aspiration in the diagnosis of actinomycosis.

An 85-year-old man had a 4-year history of recurrent pneumonia with a persistent pleural effusion. He underwent repeated bronchoscopy that revealed a right bronchus intermedius mass, but bronchial washes and biopsies remained nondiagnostic. A repeat bronchoscopy was performed, and a Wang needle aspiration of the mass was obtained that showed sulfur granules, diagnosing actinomycosis. The patient was started on appropriate antibiotic therapy. Actinomycosis must be considered in a patient with recurrent pneumonia and an endobronchial mass. Wang needle aspiration via bronchoscopy may be an important diagnostic tool.

Polymerase chain reaction to detect Mycobacterium tuberculosis in histologic specimens.

There is a need for rapid and sensitive detection of Mycobacterium tuberculosis in tissue specimens. A polymerase chain reaction (PCR)-based assay for the diagnosis of tuberculosis was evaluated in 60 formalin-fixed tissue specimens, the target for the amplification being a segment of IS6110 in the M. tuberculosis chromosome. Of the 60 formalin-fixed, paraffin-embedded tissue specimens studied, 57 showed granulomatous inflammation and 53 had been cultured for mycobacteria; 10 were positive for M. tuberculosis and three were positive for other mycobacteria. Of 60 samples, 15 showed acid-fast bacilli on special staining. When done comparatively on a positive culture for M. tuberculosis, PCR for M. tuberculosis DNA in 60 tissue samples was 100% sensitive and 93% specific, having a positive predictive value of 76.9% and negative predictive value of 100%. PCR for M. tuberculosis DNA done on tissue samples was positive for 14 of 19 patients who had a clinical diagnosis of tuberculosis, negative for all six patients with nontuberculous mycobacterial infections, and negative for all 33 patients who had a diagnosis of a disease other than mycobacterial infection. When compared with the clinical diagnosis of tuberculosis, PCR for M. tuberculosis DNA in these patients' tissues was 73.6% sensitive and 100% specific, having a positive predictive value of 100% and negative predictive value of 88.6%. These data indicate that PCR amplification is useful for detecting M. tuberculosis DNA in formalin-fixed tissue specimens, and that it can be used to increase diagnostic accuracy in patients who have perplexing diagnostic problems associated with a granulomatous tissue response.