AbstractBackground: Lymphadenitis is one of the most common extrapulmonary manifestations of tuberculosis. Fine Needle Aspiration Cytology (FNAC) of tuberculous lymph node when combined with Ziehl–Neelsen (ZN) staining for acid-fast bacilli (AFB) has a paramount value in the diagnosis of tuberculosis. Objectives: To describe the cytomorphological patterns of tuberculous lymphadenitis and their correlation with AFB positivity and to describe spectrum of morphological features seen on cytological smears of tuberculous lymphadenitis. Materials and methods: A total of 100 cases of tuberculous lymphadenitis in a tertiary hospital were studied from 2016 to 2017. Fine Needle Aspiration was performed on enlarged lymph nodes and slides were looked for various cytomorphological patterns such as pattern A— epithelioid granulomas without necrosis, pattern B— epithelioid granulomas with necrosis and pattern C— caseaous necrosis without granulomas. Ziehl–Neelsen staining was done for AFB. Cytomorphological patterns of tuberculous lymphadenitis were correlated with AFB positivity. Fisher's exact test was applied to analyze the significance of correlation between cytomorphological patterns and AFB positivity. The p value of <0.05 was considered as significant. Results: The most common cytomorphological pattern observed was Pattern B, i.e. epithelioid granuloma with necrosis. AFB positivity was seen in 18% cases and maximum was observed in pattern C smears which was statistically significant (p = 0.0422). Conclusion: Fine needle aspiration cytology of tubercular lymph node when combined with ZN staining for AFB is one of the useful and economical investigations to understand the different cytomorphological patterns and in the diagnosis of tuberculosis.
Keywords: Tuberculous lymphadenitis; Ziehl–Neelsen stain; Acid-fast bacilli; Epithelioid granuloma; FNAC lymph node; Extrapulmonary tuberculosis.