Screening for tuberculosis and its histological pattern in patients with enlarged lymph node.

Settings. Tuberculosis is a major health problem in the Republic of Yemen. Tuberculous lymphadenitis is one of the most common forms of extrapulmonary tuberculosis. Therefore, this retrospective descriptive study was conducted in Yemen to investigate the morphological pattern of tuberculous lymphadenitis, as well as to assess the reliability measures of (ZN) Ziehl-Neelsen and fluorescent methods in identification of Mycobacterium tuberculosis. Methodology. One hundred lymph nodes tissue biopsies that were previously diagnosed by conventional histopathology as having tuberculous lymphadenitis were reinvestigated. Five micron in thickness sections were obtained from formalin-fixed paraffin wax processed tissues. The sections were stained using Haematoxylin and eosin (H & E), ZN, and fluorescent methods. Results. All of the 100 specimens were proved as having histopathological pattern of tuberculosis lymphadenitis. The most major histological features were giant cell (88%), caseation (84%), epithelioid cells (80%), granuloma and caseation (68%), lymphocytes (31%), and histiocytes (4%). After staining the specimens with ZN and fluorescent, of the 100 specimens only 3 (3%) and 9 (9%) specimens were found positive, by ZN and fluorescent methods, respectively. Conclusion. Conventional ZN and fluorescent methods have limitations in diagnosis of tuberculous lymphadenitis due to their lower sensitivity. Histopathology remains the most suitable method for the diagnosis of tuberculous lymphadenitis. In cases of suspected tuberculous lymphadenitis, it is advisable to confirm with more sensitive and specific method, such as polymerase chain reaction PCR or immunohistochemistry before reporting the negative results.