PURPOSE: Fine needle aspiration (FNA), instead of more invasive excisional biopsy, has been frequently used for the diagnosis of superficial lymphadenopathy. It can easily discern metastatic conditions from non-metastatic ones, but it frequently fails to differentiate among non-metastatic conditions including tuberculous lymphadenitis (TL), necessitating surgical excision for more correct diagnosis. We examined the usefulness of polymerase chain reaction of Mycobacterium tuberculosis complex (TB-PCR) of fine needle aspirates in differential diagnosis of TL among the various superficial lymphadenopathy proved to be non-metastatic.
METHODS: We reviewed the data of patients who visited the hospitals between 2002. 7 and 2007. 3 due to superficial lymphadenopathy. Two hospitals were involved for the study, one a university-affiliated hospital where nested PCR method (primer from Bioneer, Korea)(Nested PCR) was adopted for TB-PCR, and one a community-based hospital where automated PCR Assay with AMPLICOR MTB kit (Roche Molecular System, NJ, USA)(AMPLICOR) was used. TL was diagnosed when the surgical pathology revealed chronic caseating granulomatous inflammation or the histology were compatible to TL, if not definite, along with other evidences of active tuberculosis.
RESULTS: Among the total number of 46 cases (Nested PCR 22, AMPLICOR 24) determined, 29 were diagnosed to have TL. 17 other diagnoses comprised below; Kikuchi's lymphadenitis (8), malignant lymphoma (5), Bacterial abscess with reactive lymph node hyperplasia (2), others (2). The sensitivity, specificity, PPV, and NPV of TB-PCR of the fine needle aspirates were, 45%/53%/36%, 100%/100%/100%, 100%/100%/100% and 52%/50%/53%(Total/Nested PCR/AMPLICOR), respectively.
CONCLUSION: TB-PCR of fine needle aspirates was found to be helpful for the diagnosis of TL among non-metastatic superficial lymphadenopathy, especially due to its good specificity. Further studies would be strongly required.
CLINICAL IMPLICATIONS: TB-PCR of fine needle aspirates could be performed before proceeding to invasive excisional biopsy for the differential diagnosis of superficial lymphadenopathy, especially when microscopic exam of FNA suggests benign inflammatory conditions.
DISCLOSURE: Jae-Yong Chin, No Financial Disclosure Information; No Product/Research Disclosure Information