Hepatic Tuberculosis: A Rare Cause of a Liver Mass in an Immunocompetent Host

Hepatic tuberculosis (TB) is an uncommon clinical entity seen in immunocompetent hosts and its diagnosis may be challenging. Hepatic TB may present in three main forms: diffuse hepatic involvement associated with miliary or pulmonary TB, granulomatous hepatitis, or tuberculoma/abscess that may mimic malignancy. Clinicians must maintain a high index of suspicion in order to avoid missing or delaying this diagnosis. A 24-year-old woman from the Philippines presented for evaluation of right upper quadrant (RUQ) pain and 20 lb weight loss. Five years prior to presentation, an abdominal MRI done for RUQ pain revealed a heterogeneous right liver lobe with mixed attenuation partially cystic focal lesions, punctate calcifications and peripheral biliary ductal dilatation concerning for neoplasm. She was subsequently lost to follow up. Upon re-presentation, her exam was notable for RUQ tenderness to palpation. Labs revealed total bilirubin 1.1 mg/dL, AST 169 U/L, ALT 280 U/L, and alkaline phosphatase 496 U/L. Serologic evaluation for underlying liver disease, HIV and infectious agents were negative except TB quantiferon was positive. Chest CT demonstrated scattered bilateral pulmonary nodules and a prominent right hilar lymph node. Abdominal CT revealed a complex mass in the right hepatic lobe with associated biliary ductal dilatation and calcifications concerning for metastatic malignancy. Sputum acid fast bacilli (AFB) stain and culture were negative. Fine needle aspiration of the liver mass revealed extensive granulomatous inflammation. Stains and cultures for fungi and AFB were negative. Core biopsy of the liver mass was performed, again yielding negative AFB stains and culture. Ultimately, TB PCR from the core samples returned positive. She was initiated on rifampin, isoniazid, pyrazinamide and ethambutol with continued follow up in TB clinic. This case highlights the diagnostic challenges associated with hepatic TB. While AFB stain and culture should be performed to evaluate for this entity, these are highly insensitive tests with culture yielding organisms in less than 10% of cases. TB PCR has demonstrated sensitivity of 53% with specificity of 96%, resulting in 90% positive and 76% negative predictive value. While PCR is not an ideal test, it's improved sensitivity over culture makes it extremely valuable in making the diagnosis of hepatic TB.Figure 1