Mycobacterium tuberculosis
Joseph Misdraji, MD
Key Facts
Clinical Issues
In primary TB, liver is usually involved as part of disseminated TB
Reactivation TB can involve liver along with lungs or liver alone
Evidence of pulmonary TB in 65-78% of patients
Microscopic Pathology
Numerous granulomas with or without central necrosis
Coalescence of granulomas can produce tuberculoma
Immunocompromised patients have poorly developed granulomas or abscesses
Ancillary Tests
Acid-fast stains positive in 60% of cases
Culture is more likely to be positive in cases with caseating necrosis
PCR has 53-88% sensitivity and 96-100% specificity
 Paraffin section of the liver from an autopsy of a patient who died of miliary TB shows multiple necrotizing granulomas  . |
 High-power view of hepatic miliary tuberculosis shows a granuloma with focal eosinophilic granular necrotic material  and several multinucleated giant cells  . |
TERMINOLOGY
Abbreviations
Mycobacterium tuberculosis (MTB)
Tuberculosis (TB)
Definitions
Infection by M. tuberculosis
ETIOLOGY/PATHOGENESIS
