From the Guidelines
Yes, a liver fine needle biopsy (FNB) can diagnose tuberculosis (TB) affecting the liver, but it is typically not the first-line diagnostic approach for suspected TB. This procedure involves inserting a thin needle through the skin into the liver to extract a small tissue sample for examination. When TB affects the liver (hepatic tuberculosis), the biopsy may reveal characteristic granulomas with caseous necrosis and the presence of acid-fast bacilli, which are hallmarks of TB infection. The tissue sample can also be cultured to grow Mycobacterium tuberculosis or tested using polymerase chain reaction (PCR) techniques for more rapid identification 1.
To minimize sampling error and ensure an accurate diagnosis, it is essential to obtain a biopsy specimen of sufficient size, with a recommended length of at least 2.0 or 2.5 cm and a width obtained with a 16-gauge needle 1. The British Society of Gastroenterology, the Royal College of Radiologists, and the Royal College of Pathology also emphasize the importance of liver biopsy in clinical practice, including its use in diagnosing and staging liver disease, predicting prognosis, and informing treatment decisions 1.
Some key points to consider when performing a liver FNB for TB diagnosis include:
- The distribution of tuberculous lesions in the liver can be patchy, potentially leading to sampling errors 1
- A 16-gauge needle is recommended to obtain a biopsy specimen of sufficient size 1
- The biopsy specimen should be at least 2.0 or 2.5 cm in length to minimize sampling error 1
- Liver FNB is typically not the first-line diagnostic approach for suspected TB, but rather used when other diagnostic methods have been inconclusive or in patients with risk factors for TB 1
If hepatic TB is diagnosed, standard anti-tuberculosis treatment typically includes a combination of isoniazid, rifampin, ethambutol, and pyrazinamide for two months, followed by isoniazid and rifampin for an additional four months, though regimens may vary based on drug resistance patterns and patient factors.
From the Research
Liver Fine Needle Biopsy for Diagnosing Tuberculosis
- A liver fine needle biopsy (FNB) can be used to diagnose tuberculosis (TB) [(2,3,4)].
- The diagnosis of hepatic TB can be challenging due to non-specific clinical and imaging features [(3,4)].
- Image examination associated with image-guided fine needle aspiration biopsy is considered the best diagnostic method for hepatic TB 2.
- Liver biopsy with nucleic acid testing of liver tissue samples is the most specific diagnostic modality for hepatic TB 3.
Sensitivity of Fine Needle Biopsy
- The sensitivity of smear microscopy for acid-fast bacilli on liver biopsy is relatively low, with a median sensitivity of 25% 3.
- Histology of caseating granulomas on liver biopsy has a median sensitivity of 68% 3.
- Polymerase chain reaction (PCR) for TB on liver biopsy has a median sensitivity of 86% 3.
Role of Fine Needle Biopsy in Diagnosing Abdominal Tuberculosis
- Ultrasound-guided fine needle aspiration cytology (FNAC) can be used to diagnose abdominal tuberculosis, including hepatic TB 5.
- FNAC has a high sensitivity in diagnosing tuberculosis in lymph nodes and spleen, but is less sensitive in diagnosing hepatic TB 5.
- Aspiration cytology can be used to diagnose TB in various sites, including lymph nodes, bone, and soft tissues 6.