FNAC
FNAC stands for Fine Needle Aspiration Cytology. It is a diagnostic procedure that involves using a thin, hollow
needle to remove a small sample of tissue or cells from an organ or mass for microscopic examination. FNAC is
commonly used to diagnose various conditions, including cancers, infections, and other inflammatory or benign
disorders.
USG-guided FNAC in Liver Disease
Ultrasound-guided Fine Needle Aspiration Cytology is a procedure in which ultrasound imaging is used to guide
the insertion of a fine needle into the liver to aspirate (withdrawal) cells or tissue for analysis. This technique combines
the precision of ultrasound imaging with the diagnostic capability of FNAC, making it a valuable tool in the evaluation of
liver diseases.
Indications
1. Liver Masses/Tumors
2. Cirrhosis and Portal Hypertension
3. Infections and Inflammatory Conditions
4. Non-invasive Alternative to Liver Biopsy
Contraindications
1. severe thrombocytopenia (low platelet count)
2. Vascular Liver Lesions
3. Severe Hemodynamic Instability
4. Lack of Safe Needle Path - If the lesion is located near major blood vessels, bile ducts, or vital structures where
there is a high risk of injury.
Advantages of USG-guided FNAC:
1. Minimally Invasive:
USG-guided FNAC is a relatively simple, outpatient procedure that requires only local anesthesia, making
it a less invasive option compared to traditional liver biopsy.
2. Real-time Imaging:
Ultrasound guidance allows for real-time visualization of the liver and the lesion being aspirated, which
increases the accuracy of the procedure and minimizes the risk of complications, such as puncturing a
blood vessel.
3. Reduced Complication Risk:
The use of ultrasound guidance helps minimize the risk of injury to surrounding structures (such as
blood vessels or the gallbladder) and improves the likelihood of obtaining an adequate sample.
4. Quick and Cost-effective:
The procedure is relatively quick and cost-effective compared to more invasive techniques like liver
biopsy, which may require hospitalization and more extensive resources.
Procedure of USG-guided FNAC:
1. Preparation:
The patient may be asked to fast for several hours before the procedure. The procedure is usually
performed on an outpatient basis.
A local anesthetic is applied to the area of the liver being aspirated.
2. Guidance and Aspiration:
The ultrasound probe is placed on the patient's abdomen, and the liver lesion is identified.
A fine needle is then inserted through the skin into the lesion under real-time ultrasound guidance. The
needle is used to withdraw a small sample of tissue or cells from the lesion.
3. Post-procedure Care:
The patient may be observed for a short time after the procedure to monitor for any complications like
bleeding or discomfort.
Mild pain or soreness at the needle insertion site is common, but severe pain or complications like
significant bleeding are rare.
Limitations of USG-guided FNAC in Liver Disease:
1. Inadequate Sample:
Obtaining a good-quality sample can sometimes be challenging, especially in certain types of lesions, which
may require multiple attempts or additional imaging techniques.
2. Sampling Error:
FNAC is based on the cellular composition of the aspirated tissue, which might not always reflect the entire
lesion's characteristics, leading to possible diagnostic inaccuracies. This can be especially true for lesions that
are heterogeneous or have areas of necrosis.
3. Limited to Superficial Lesions
While ultrasound guidance can accurately target lesions, very deep or small lesions that are difficult to
visualize may pose challenges for the procedure.
4. Non-diagnostic Results:
In some cases, the aspirated sample may not provide a definitive diagnosis, necessitating further testing,
such as biopsy or advanced imaging.
Role in Liver Disease Diagnosis:
Hepatocellular carcinoma (HCC): USG-guided FNAC is commonly used in the diagnosis of liver cancer. It helps
confirm the presence of malignant cells in suspected lesions, guiding treatment decisions such as surgical
resection, liver transplantation, or chemotherapy.
Liver Metastasis: USG-guided FNAC can identify metastatic tumors from other primary cancers (e.g., colorectal,
breast, lung), which often spread to the liver.
Infectious Lesions: In cases of suspected liver abscesses, FNAC can help distinguish between different causes of
infection, such as bacterial, fungal, or parasitic abscesses, and guide appropriate antimicrobial therapy.
Benign Liver Lesions: In some cases, USG-guided FNAC helps differentiate between benign liver conditions, such
as hemangiomas or focal nodular hyperplasia, and malignant lesions, avoiding unnecessary surgeries or
interventions.
Conclusion:
USG-guided FNAC is a valuable, minimally invasive tool in the diagnosis and management of various liver diseases. Its
ability to provide quick, accurate, and real-time guidance for tissue sampling helps clinicians make informed decisions
regarding the treatment of liver conditions, especially when more invasive procedures like liver biopsy may not be
feasible or appropriate. Despite its limitations, it remains an essential diagnostic tool in hepatology.
