Aspiration Cytology: Principle of FNAC (Fine Needle Aspiration Cytology). Procedure of FNAC. Indications of FNAC. Uses of FNAC. FNAC Advantages and Disadvantages Unit IV. Immunopathology and Cytology DMLT HSBTE.

Aspiration Cytology

Aspiration: Aspiration is the process of drawing in or suctioning out fluids, gases, or other substances using a device such as a needle, syringe, or suction catheter. Aspiration is commonly used to remove fluids or tissues from a specific area of the body for diagnostic or therapeutic purposes.

Fine Needle Aspiration (FNA) is a specific type of aspiration technique used in medicine to collect a sample of cells from a lesion or mass for cytological examination.

Cytology: Cytology deals with the study of cells, including their structure, function, and abnormalities. Cytology involves the microscopic examination of cells collected from tissues, organs, or bodily fluids. Common cytological techniques are Fine Needle Aspiration Cytology (FNAC), PAP smears, and the examination of fluids like pleural or peritoneal fluid.

Principle of FNAC (Fine Needle Aspiration Cytology):

Fine Needle Aspiration Cytology (FNAC) is a diagnostic technique used to obtain cellular material for examination from a suspicious lesion or mass. The principle of FNAC involves the following aspects:

• 1. Minimally Invasive Technique: FNAC is a minimally invasive procedure. It uses a thin, hollow needle to aspirate (suction out) a small sample of cells from the targeted tissue or lesion. FNAC allows for the sampling of cells without major surgery.

• 2. Cellular Sample Collection: The goal of FNAC is to collect a representative sample of cells from the target area. This can include solid masses, cystic lesions, or enlarged lymph nodes.

• 3. Lesion Selection: FNAC is typically performed on lesions or masses that are easily accessible with a thin needle. Common sites for FNAC include the thyroid, breast, lymph nodes, and soft tissues.

• 4. Procedure Technique: A fine needle attached to a syringe is inserted into the lesion. A negative pressure is applied by withdrawing the plunger of the syringe. The negative pressure helps in aspirating cells from the tissue into the needle. Multiple passes may be made to ensure an adequate sample.

Procedure of FNAC

The procedure for Fine Needle Aspiration Cytology (FNAC) involves a series of steps. The following are general guidelines for the FNAC procedure:

Pre-procedure Preparation:

• 1. Patient Consent: Obtain informed consent from the patient after explaining the procedure, its purpose, and potential risks.

• 2. Patient Positioning: Position the patient depending on the location of the lesion. The patient may need to lie down or sit, depending on the area to be aspirated.

• 3. Anesthesia (if necessary): Local anesthesia may be administered to minimize discomfort during the procedure.

Procedure Steps

• 1. Identification of Lesion: Identify the target lesion either through physical examination or with the assistance of imaging techniques such as ultrasound, CT scan, or fluoroscopy.

• 2. Needle Selection: Choose a fine gauge needle (typically 21-25 gauges) attached to a syringe. The needle size depends on the nature and location of the lesion.

• 3. Skin Antisepsis: Cleanse the skin overlying the lesion with an antiseptic solution to reduce the risk of infection.

4. Needle Insertion: Insert the fine needle into the lesion. Move needles back and forth in different directions. It ensures the collection of cells from different areas.

5. Aspiration: Apply negative pressure by withdrawing the plunger of the syringe while the needle is in the lesion. This helps aspirate cellular material entry into the syringe.

6. Withdrawal of Needle: Carefully withdraw the needle from the lesion.

7. Preparation of Smears: Expel the aspirated material onto glass slides. Multiple smears may be prepared for a complete analysis.

8. Staining: PAP staining and Leishman’s staining are used.

Post-procedure Steps

• 1. Patient Observation: Observe the patient for any immediate complications or discomfort.

• 2. Documentation: Document the details of the procedure, including the site aspirated, the appearance of the aspirated material, and any relevant findings.

• 3. Communication of Results: Communicate the preliminary results to the patient or referring physician, if possible.

Precautions

• 1. Avoiding Blood Contamination: Care should be taken to minimize blood contamination, especially in lesions with vascularity.

• 2. Needle Track Seeding: Minimize the risk of needle track seeding by avoiding unnecessary passes through the lesion.

• 3. Handling and Transport of Samples: Ensure proper handling and transport of collected samples to the laboratory for further analysis.

• 4. Infection Control: Adhere to infection control measures to prevent complications.

• 5. Quality Control: Maintain strict quality control measures to ensure accurate and reliable results.

Indications of FNAC

Fine Needle Aspiration Cytology (FNAC) is a valuable diagnostic procedure used to obtain cellular material from lesions for examination under a microscope. FNAC is indicated in various clinical situations where a non-invasive method of obtaining tissue samples is desirable. The following are common indications for FNAC:

A. If Surgery is not Possible:

1. Patient refusal: Some patients may decline surgery due to personal reasons, beliefs, or fears.

2. Difficult or dangerous location: Certain masses or conditions may be situated in anatomically risky areas. It makes surgical intervention impractical.

3. Investigative mass in poor-risk patients: In cases where the patient's overall health status is poor or they have medical conditions surgery may not be considered a viable option.

B. If surgery is contraindicated: Presence of malignant mass. Mass or cyst. Elder patient, pregnancy, etc.

Uses of FNAC

Fine Needle Aspiration Cytology (FNAC) is a diagnostic procedure that involves the collection of cellular material from a suspicious lesion or mass using a thin, hollow needle. FNAC has various uses across different medical specialties:

• 1. Diagnosis of Tumors: It determines the nature of the lesion and helps in treatment planning.

• 2. Breast Lesions: It helps differentiate between benign breast conditions and breast cancer.

• 3. Thyroid Nodules: It aids in determining whether a nodule is benign or malignant.

• 4. Lymph Node Assessment: FNAC is used to evaluate enlarged lymph nodes for signs of infection, inflammation, or cancer.

• 5. Salivary Gland Lesions: It assists in distinguishing between various benign and malignant conditions in salivary gland lesions.

• 6. Liver Lesions: FNAC differentiates between benign and malignant conditions in liver lesions. It is particularly useful in patients with liver disease.

• 7. Pancreatic Lesions: It helps to determine the nature of the lesion, tumor, and cyst in the pancreas.

• 8. Kidney Lesions: It assists in distinguishing between benign and malignant lesions in the kidney.

• 9. Pleural and Peritoneal Effusions: FNAC is used to analyze cells in pleural or peritoneal fluid. It helps identify the underlying cause, such as infection, inflammation, or malignancy.

• 10. Palpable Masses: It provides a quick and minimally invasive way to assess the nature of the mass in palpable masses or lumps.

• 11. Therapeutic Monitoring: FNAC may be used for monitoring the response to treatment in certain cases, such as in cancer patients undergoing chemotherapy.

• 12. Quick Diagnosis: FNAC provides a rapid diagnosis, allowing for timely decision-making regarding further diagnostic tests or treatment plans.

Advantages OF FNAC

• 1. Easy to perform diagnostic Tests

• 2. Less painful than the knife biopsy process.

• 3. Rapid and Accurate. Helpful in early treatment.

• 4. Mass investigation without cutting out.

• 5. Preoperative knowledge of deep-sighted lesions.

Disadvantages of FNAC

• 1. Spreading cancerous cells is possible.

• 2. It may cause internal bleeding.

• 3. The point of the needle may miss the target cells. Thus inaccuracy in results may occur.

Dr Pramila Singh.