Histopathological Cellular and Diagnostic Features of Tuberculous Lymphadenitis

Background: Tuberculosis (TB) remains a global health problem with 25% of the world’s population infected from the causative agent Mycobacterium tuberculosis(MTB). Indian ranks first amongst the eight countries reported to have highest burden of MTB across the globe. TB is categorized into pulmonary and extrapulmonary(EPTB); the most common clinical manifestation of EPTB being tuberculous lymphadenitis(LNTB). LNTB generally occurs due to reactivation of latent infection and cervical lymph nodes are the most common sites. Objective: The present research work was conducted to explore disease spectrum of LNTB highlighting specific histopathologic features. Materials and Methods: Twenty-one patients with clinically diagnosed LNTB were included and one lymph node biopsy was obtained from each patient. The formalin-fixed paraffin tissue sections were subjected to standard hematoxylin & eosin staining (H & E stain) to understand different histologic features of LNTB. Results: LNTB displayed a disease spectrum which can be categorized into four broad categories as: 1. Early granulomas(n=2); 2. Non-caseating granulomas(n=12); 3. Caseating granulomas(n=6); 4. Massive extensive caseation without Langhan’s giant cells(n=1). The well-formed, non-necrotic, epithelioid cell granulomas were prominent feature of LNTB in our study. Conclusion: The above study supports the existence of a disease spectrum of LNTB with histologic features ranging from early granulomas to massive caseation necrosis. This can aid clinicians for better diagnosis of LNTB so to aid for early detection and an appropriate treatment of the disease.