Eosinophilic Structure: Should it be Included in Routine Cytology Reporting of Tuberculosis Lymphadenitis?

Abstract

Fine needle aspiration cytology is a simple, rapid procedure routinely employed for the diagnosis of tuberculosis lymphadenitis. Positivity for acid fast bacilli (AFB) in Ziehl-Neilsen stained smear is still considered as gold standard for diagnosis of Tuberculosis, but all lesions may not yield AFB, thus pose diagnostic problems. Few cytomorphological changes i.e. Eosinophilic structure (ES) in the stained smears correlates with the presence of AFB thus, helping us in rapid diagnosis. To evaluate the correlation between AFB and ES in necrotic lymph node aspirates. This is a retrospective study conducted from January to December 2014. Lymphnodes upon purulent aspiration which were reported as granulomatous lymphadenitis suggestive of tuberculosis were included in the study. All the stained smears (H&E, MGG and ZN Stains) for each case were retrieved from the files and rescreened for the presence of ES, granulomas and AFB. Presences of ES were correlated with AFB. Stastistical analysis was done using Chi-square test. Our study included 103 cases. The common age group involved was 21-40 years, with female predominance. Cervical lymph nodes were most commonly involved. In relation to ES and AFB, four different cytological pictures were seen i.e., ES and AFB-(31%); ES-AFB+(16.5%); ES+, AFB+(39%); ES+AFB-(14.5%). Chi-square test showed a highly significant stastistical association between ES and AFB with p=0.001. Eosinophilic structure is one of the cytomorphological features to be considered in necrotic lymph node aspirate which has a significant correlation with AFB in the smears. Hence pathologist should search for this, and it should be included in routine cytology reporting of tuberculosis lymphadenitis.