The histological patterns of tuberculous lymphadenitis as seen at Kenyatta National Hospital

Abstract

This is a retrospective study of the histological patterns of tuberculous lymphadenitis. Four histological patterns of tuberculosis have been described. The main objective was to review the histology of tuberculous lymphadenitis as seen at Kenyatta National Hospital and categorise it in the generally accepted histological spectrum of tuberculosis made-up of the four groups that define the spectrum. The study showed that such a spectrum forms a rational basis for the histological classification that would relate to the immune status. The spectrum has two polar groups, at one end morphologically characterised by extensive necrosis and poor and disorganised cellular response and abundant tubercle bacilli. This group of patients are likely to have a relatively rapidly progressive and disseminated disease. The other end of the spectrum is characterised by a proliferative cellular lesion with lymphocytes, macrophages and fibroblasts and minimum tissue destruction and scanty microorganisms. The middle groups show intermediate responses. This classification has been found to be reproducible and its main application lies in its extrapolation to the likely clinical course of the disease. The finding that most of the cases lay in the intermediate groups of the spectrum agrees with the local experience that our patients show a relatively poor immunological response to Mycobacterium tuberculosis the suggested compounding factors being concurrent multiple parasitic infections and poor nutrition. Of the two methods for demonstrating acid-fast bacilli in tissue that were used the fluorochrome method proved the more sensitive over the traditional time-honoured Ziehl-Neelsen method.