Polymerase chain reaction detection of Mycobacterium tuberculosis from fine-needle aspirate for the diagnosis of cervical tuberculous lymphadenitis.

BACKGROUND

Despite its well-established usefulness in the diagnosis of cervical tuberculous lymphadenitis, fine-needle aspiration cytology (FNAC) has several limitations in its clinical applications, especially when the presence of acid-fast bacilli is not proven. Furthermore, fine-needle aspirate is sometimes inadequate for diagnosis, and the sensitivity and specificity of this technique for cervical tuberculous lymphadenitis has not been firmly established.

OBJECTIVE

The authors performed Mycobacterium tuberculosis polymerase chain reaction (PCR) for mycobacterial DNA sequences from the remainder of fine-needle aspirate after cytological examination and evaluated its diagnostic efficacy in clinical situations.

METHODS

Conventional diagnostic procedures including FNAC and M tuberculosis PCR were performed simultaneously in 29 cases that had been suspected to be cervical tuberculous lymphadenitis on patients' first visit. The results of FNAC and M tuberculosis PCR were compared with the clinical outcomes after several months of follow-up and pathological results from open biopsy of some cases.

RESULTS

Among the 17 cases of cervical tuberculous lymphadenitis diagnosed in clinical situations, M tuberculosis DNA was found by PCR in 13 cases (76.4%). Negative findings on PCR were achieved in 12 cases, which revealed non-granulomatous lymphadenopathy.

CONCLUSION

From these results, we conclude that M tuberculosis PCR using the remainder of aspirate for cytological examination is a very useful tool for the diagnosis of cervical tuberculous lymphadenitis, and its clinical application with FNAC could reduce the necessity for open biopsy.