Mycobacterium tuberculosis
Laura W. Lamps, MD
Key Facts
Clinical Issues
GI symptoms, rather than pulmonary, may be initial presentation
Macroscopic Features
Frequency of involvement: Ileocecum > jejunoileum > appendix > ascending colon
Endoscopic findings
Ulcers
Multiple &/or segmental involvement with skip areas
Inflammatory nodules
Microscopic Pathology
Caseating granulomas
Associated rim of lymphocytes
Acid-fast stains may demonstrate organisms
Culture &/or molecular testing may be required
 Hematoxylin & eosin stained biopsy shows confluent epithelioid granulomas  in the right colon. There are scattered multinucleate giant cells and associated lymphocytes. |
 Hematoxylin & eosin stained section of an esophageal biopsy shows a palisading granuloma  with central caseous necrosis in the submucosa of the esophagus. (Courtesy P. Ferguson, MD.) |
TERMINOLOGY
Abbreviations
Mycobacterium tuberculosis
Synonyms
Tuberculosis (TB)
Definitions
Granulomatous disease caused by acid-fast M. tuberculosis
Common in developing countries
Resurgence in developed countries due to AIDS, immigrant populations, overcrowding
