[Efficacy of PCR for the differential diagnosis of tuberculosis in granulomatous lesions of paraffin-embedded formalin fixed tissues]. / Eficacia del diagnóstico diferencial de tuberculosis mediante reacción de polimerasa en cadena en lesiones granulomatosas de tejidos fijados en formalina e incluidos en parafina.

ABSTRACT

BACKGROUND: Granulomatous lesions occur in tuberculosis (TB), other infections, toxic, allergic, and autoimmune diseases among others. In absence of a an acid-fast bacilli (AFB) confirmation of TB is necessary. OBJECTIVE: To assess the efficacy of PCR for TB detection and to correlate with granuloma histology and AFB staining. METHODS: We analyzed 380 fixed paraffin-embedded tissues (PETs) of granulomas with and without caseous necrosis; suppurative; sarcoidal; or of chronic nonspecific nature. Nested PCR-IS6110 for Mycobacterium tuberculosis complex (MTB) and a nested pan-Mycobacterium for the hsp65 gene were used for Mycobacterium spp detection. RESULTS: PCR was more sensitive than AFB staining for all five catagories of granulomas G1 PCR 71%, AFB staining 28%. G2 PCR 37%, AFB 8%. G3 PCR 17%, AFB staining 7%. G4 PCR 8%, AFB staining 4%. G5 PCR 6%, AFB staining 0%. CONCLUSIONS: Molecular diagnosis of TB using PCR-based testing is a fast, efficacious and sensitive method that increased the accuracy of PET histological diagnosis associated with granulomatous lesions.