Granulomatous Reaction at the Site of Positive Tuberculin Skin Test is a Marker of Active TB (Clinical and Histopathological Study)

摘要

Background: Medical authorities all over the world did not pay much attention to diagnostic value of positive tuberculin test but our observation suggest that the tuberculin test with histopathological evaluation could be very helpful in establishing clinical diagnosis of tuberculosis (TB) without the essential need for other diagnostic tools. Objective : To study all positive tuberculin reaction and to do histopathological examination in order to get objective findings in that are helpful for clinical diagnosis of TB. Patients and Methods : This is descriptive and histopathological study, carried out in Center of Dermatology and Venereology, Baghdad Teaching Hospital from January 2017 to January 2018. Twenty patients were enrolled in the current study, their ages ranged between 19-62(53.32 +/- 11.9) years, full history taken including personal or family history of pulmonary or extra-pulmonary TB, BCG vaccination, and the measurement of TST as had carried out in The Specialist National Center for Pulmonary Diseases and those with positive tuberculin 10 mm and more were included. Punch biopsy taken from the site of positive TST after (2) days of doing the test in (10) patients, and around (10) days in (8) patients and in (2) patients 6 weeks after positive reaction and these biopsies were processed for HResults : The total biopsies from positive TST were 20, 10 of them taken from patients diagnosed with active TB, anti TB therapy was started for them. The other 10 biopsies taken from patients diagnosed latent TB. Regarding the patients with active TB, their histopathological results revealed: 10(100%) biopsies had superficial and deep perivascular and periadnexial lymphocytic and lymphohistiocytic infiltrate, vascular dilatation, dermal edema, 9(90%) had basal liquefactive degeneration, 2(20%) biopsies revealed dermatitis like picture while panniculitis was seen in 4(40%) biopsies. Granuloma was detected in 7(70%) patients. While in latent TB patients including 10 patients, the biopsies of positive tuberculin test site had shown the following: 10(100%) biopsies had superficial and deep perivascular and periadnexial lymphocytic and lymphohistiocytic infiltrate, vascular dilatation, dermal edema, 9(90%) basal liquefactive degeneration, 2(20%) biopsies dermatitis like picture while panniculitis in 3(30%) biopsies and granuloma in 4(40%) patients. Conclusion : The degree of inflammatory reaction at the positive TST might predict the future risk of developing TB in a patient with a latent TB. While the presence of granuloma is more suggestive of the present active TB or having a higher risk of developing active TB in the near future.