Cytopathological patterns of tuberculous lymphadenitis: an analysis of 126 cases in a tertiary care hospital

Background: Tuberculous lymphadenitis is one of the most common causes of lymphadenopathy in developing countries. Fine needle aspiration cytology (FNAC) has important role in the diagnosis of tuberculous lymphadenitis. The objective of this study was to evaluate the cytopathological patterns of tuberculous lymphadenitis and to correlate with Ziehl-Neelsen (ZN) staining.Methods: FNAC of 126 cases diagnosed as tuberculous lymphadenitis over a period of three years were reviewed. FNAC findings were categorized into three patterns: pattern A- epithelioid granuloma without caseous necrosis, pattern B- epithelioid granuloma with caseous necrosis, pattern C- caseous necrosis without epithelioid granuloma. Chi-square test was done to correlate cytopathological pattern and acid fast bacilli (AFB) positivity.Results: Tuberculous lymphadenitis was most frequent in the age group of 21-30 years (40.5%). Most common lymph node involved was cervical lymph node (82.53%). The most common pattern observed was Pattern B- Epithelioid granuloma with caseous necrosis in 53.17% cases. Overall AFB positivity was seen in 34.92% cases. Maximum AFB positivity was seen in Pattern C- Caseous necrosis without epithelioid granuloma in 81.81% cases. Serum adenosine deaminase (ADA) was elevated in 66.66% patients.Conclusions: FNAC is safe and cost effective diagnostic tool for the diagnosis of tuberculous lymphadenitis. Ziehl-Neelsen stain for Acid fast bacilli and Serum ADA can be used as an adjunctive tool for the diagnosis of tuberculous lymphadenitis.