The cytologic diagnosis of tuberculosis in pleural effusions

This paper reports on eight patients who had cytologic findings suggestive of florid pleural tuberculosis in pleural exudates. The suggestive diagnosis in each case was confirmed either by a pleural biopsy, culture of Mycobacterium tuberculosis from the aspirated fluids or clinical improvement from the administration of tuberculotherapy. The pleural effusion from tuberculosis is characterized by the presence of abundant lymphocytes in the smear. The nuclei of the lymphocytes show characteristic morphologic features. The two most important differential diagnoses are those effusions rich in lymphocytes due to nonspecific causes and effusions containing numerous tumor cells from a well-differentiated lymphosarcoma.