FINE NEEDLE ASPIRATES OF ENLARGED LYMPH NODES. ROLE OF ZIEHL NEELSEN STAIN IN THE DIAGNOSIS OF TUBERCULOSIS

ABSTRACT
Background: Lymph node tuberculosis (LNTB) is the leading form of extra pulmonary tuberculosis and common in our
country. Acid Fast Bacilli (AFB) detection by Ziehl-Neelsen (ZN) method in the fine needle aspirate from these lymph
nodes is confirmatory.
Objective: To assess the diagnostic utility of Ziehl-Neelsen staining in lymphadenopathy cases, since it is commonly
used method in the diagnosis of TB.
Methods: A total of 150 cases of tuberculous lymphadenitis diagnosed by fine needle aspiration cytology (FNAC)
were included in this study. Smears of the aspirates from all these cases were stained with Ziehl-Neelsen stain and
examined by the light microscope. Results of Acid Fast Bacilli by Ziehl-Neelsen and cytomorphology by fine needle
aspiration cytology were compared.
Results: The classic cytomorphological pattern of tuberculous lymphadenitis (epithelioid granulomas, Langhan’s giant
cells and caseous necrosis) by Fine Needle Aspiration Cytology was seen in 150 cases. These were divided into three
categories among which maximum cases (80.95%) were confirmed in the smears showing caseous material only. By
concluding the results routine Ziehl-Neelsen staining confirmed Acid Fast Bacilli in 90 (60 %) cases.
Conclusion: Ziehl-Neelsen staining if coupled with fine needle aspiration cytology of suspected tuberculous lymphadenopathy
cases can confirm diagnosis of tuberculosis.
Keywords: Ziehl-Neelsen stain; Tuberculosis (TB); Fine needle aspiration cytology (FNAC); Acid-fast bacilli; lymph node