Abstract
Objectives This study aimed to investigate the presence of the Mycobacterium tuberculosis bacillus in formalin-fixed paraffin-embedded (FFPE) oral samples that contained granulomas with caseous necrosis.
Materials and Methods FFPE biopsies that showed granulomas with caseous necrosis, suggestive of the diagnosis of tuberculosis, were selected. M. tuberculosis was searched by Ziehl-Neelsen staining (ZN), immunohistochemistry (IHC), nested-PCR, and GeneXpert® MTB/RIF assays.
Results Nine samples showing granulomas with caseous necrosis were selected. There was a predominance of males (2.5:1), with a mean age of 50 (19-89) years, and the tongue was the most affected anatomical site (n=4). The bacillus was not identified by the ZN technique in any sample, and IHC staining showed a coarse granular pattern staining, suggestive of M. tuberculosis, in three of them. Nested-PCR and the GeneXpert® MTB/RIF assays were positive in two and three of the samples, respectively.
Conclusions Molecular tests and IHC may be useful auxiliary methods for suspected cases of tuberculosis.
Clinical Relevance This study provides information on the utilization and efficacy of diagnostic methods necessary to aid pathologists in accurately diagnosing oral TB lesions.