Cytomorphological spectrum and Ziehl-Nelson staining in suspected tuberculous lymphadenitis: A study of 100 cases

Indrani Dhawan 1 , Oneal Gupta 1 , Ankit Kaushik* 1 , Sunil Ranga 1 , Dimple Kasana 2 , Prem R Gupta 1 1 Department of Pathology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India 2 Department of Microbiology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India Background: Tuberculosis (TB) is the leading cause of death from a curable infectious disease. The situation is further worsened by a resurgence of the disease in immunocompromised AIDS cases. Lymphadenitis is the most frequent form of extrapulmonary tuberculosis. The diagnosis of tuberculous lymphadenitis remains challenging in spite of the availability of various diagnostic tools. Aims: The present study aims at studying different cytomorphological patterns in suspected cases of tuberculous lymphadenitis and the efficacy of cytology and Ziehl-Nelson (ZN) staining in diagnosing tuberculous lymphadenitis in these different patterns. Methods: One hundred cases clinically suspected of tuberculous lymphadenitis were studied (over a period of one year) with the aid of fine needle aspiration cytology (FNAC) complemented with AFB staining. The cytomorphological spectrum along with AFB positivity in different groups was compared. Results: Maximum AFB positivity was seen in cases showing cytomorphological features consistent with a granulomatous lesion with necrosis (i.e. in 10 out of 21 cases; 48%). The difference in AFB positivity between various cytomorphological groups was found to be statistically significant (p < 0.01) especially between cases showing caseating granuloma and those showing non-caseating granuloma or reactive lymphadenitis at 1% level of significance. The maximum sensitivity of ZN stain was found in cases showing caseating granuloma, and was nil in cases showing non-caseating granuloma and cases showing reactive lymphadenitis. Conclusion: The maximum AFB positivity is seen in cases showing cytomorphological features consistent with a granulomatous lesion with necrosis. A combination of conventional techniques (FNA and ZN staining for AFB) and newer diagnostic techniques must be applied for the rapid and early diagnosis of tuberculosis in paucibacillary specimens to achieve maximum sensitivity. A-37 Cytomorphological spectrum of TBLN Annals of Pathology and Laboratory Medicine, Vol. 02, No. 01, Jan-Mar 2015 Introduction Tuberculosis (TB) is the leading cause of death from a curable infectious disease. Despite national and international tuberculosis control programs, TB, a treatable condition, is rampant in India. The situation is further worsened by a resurgence of the disease in immunocompromized AIDS cases. [1] Lymphadenitis is the most frequent form of extrapulmonary tuberculosis, usually occurring in the cervical region ("scrofula"). [2] The diagnosis of tuberculous lymphadenitis remains challenging in spite of the availability of various diagnostic tools. Conventional microbiological methods, like ZN staining and culture for Mycobacterium tuberculosis, are traditionally used in the diagnosis of tuberculous lymphadenitis. [3] However, none of these methods alone can diagnose all cases of TB lymphadenitis. Standard diagnostic algorithm for tuberculous lymphadenitis in India recommends FNAC with ZN staining for acid fast bacilli (AFB) in clinically suspected cases. [4] Detection of AFB by conventional microscopy is simple and rapid but lacks adequate sensitivity. Materials and Methods The present prospective study was conducted in the Department of Pathology and Microbiology, Safdarjung hospital & VMMC (a tertiary care hospital), New Delhi. One hundred cases clinically suspected of tuberculous lymphadenitis were studied (over a period of one year) with the aid of FNAC complemented with AFB staining. Clinically suspected cases between 15 years and 65 years of age, referred to the Department of Histopathology were included in the study. An informed express consent of the patient was taken in each case. Relevant clinical history and findings were recorded. FNAC was performed in all the cases using a 22G needle. The material aspirated on FNA was used to make the smears. Air dried smears were stained immediately with Giemsa stain for cytomorphological study and ZN stain for AFB. The cytological criteria for diagnosis of tuberculosis were taken as: 1. FNA cytology showing epithelioid cell granulomas with or without multinucleated giant cells and caseation necrosis. 2. Presence of AFB (by ZN stain) in smears showing necrosis only/non-caseating granulomas/acute suppurative lymphadenitis. 3. Cases showing necrosis only/non-caseating granulomas/acute suppurative lymphadenitis without demonstration of AFB were considered as suspicious of TB. The efficacy of FNAC and ZN stain in different cytomorphological spectrums is compared.