What Is Fine Needle Aspiration Cytology?
Fine needle aspiration cytology (FNAC) is considered by oral clinicians as a rapid and reliable diagnostic tool with adequate safety and high-quality standards. It is efficiently used to detect varied lesions be it of the oral cavity or of the salivary glands and is especially useful in the detection of oral cancers or tumors. This important diagnostic technique is mainly used for head and neck lesions such as thyroid gland and salivary gland swellings, lymphatic swellings or tumors, etc.
How Efficient Is Fine Needle Aspiration Cytology in Oral Lesions?
As per medical research, the hard palate constitutes nearly 33.33 % of all aspirations and hence is the predominantly aspirated site of the oral cavity. The parotid gland is similarly the most predominant gland aspirated in maximum patients up to approximately 60.3 % when the salivary glands are involved in various benign or malignant lesions. Non-neoplastic lesions are easily detected by FNAC and approximately constitute around 18 % while nearly 81 % of the lesions aspirated may tend to be neoplastic lesions or rather of neoplastic origin. Pleomorphic adenoma which constitutes nearly 28 % of all oral lesions is also another common oral benign lesion after the lesions of the hard palate and the parotid salivary gland. FNAC is most useful in oral cancer detection of squamous cell carcinoma which constitutes nearly 60 % of all malignant lesions of the oral cavity. These oral cancers may either involve the tongue, buccal mucosa, or salivary glands. As per diagnostic research and rating of technique efficacy, FNAC has been found to be an extremely beneficial diagnostic test for overall sensitivity, specificity, and accuracy for the detection of oral premalignant, malignant, or benign tumors of the oral cavity.
What Is the Procedure of Fine Needle Aspiration Cytology?
FNAC technique is also the mainline standard and reliable diagnostic tool for oral and oropharyngeal lesions detection and is performed in the following way :
The overlying mucosa is firstly cleaned with spirit and a standard 22 to 23-gauge needle is connected to a plastic syringe.
The area to be aspirated is immobilized using the thumb and index finger of the operator.
The needle is then inserted into the lesional skin.
Post the insertion of the puncture needle into the lesion or the swelling, the operator performs a quick motion.
The syringe plunger would then create a negative pressure within the syringe as well as the lumen of the needle that would suck the lesion contents.
After the retrieval of a portion of the lesion’s content or material, the needle can be moved back and forth three to four times while directing it into different areas of the swelling or mass.
The aspirate will then be placed on a slide by applying gentle pressure and smears would be prepared for histopathologic examination.
The common stains that are used according to standard guidelines or international protocols include May-Grunwald Giemsa (MGG), Papanicolau (PAP), or hematoxylin and eosin stains. When the PAP or the hematoxylin and eosin staining slides are prepared, they need to be immediately fixed in Carnoy’s fixative or 95 % ethanol solution. In case the MGG staining is done, then the slides would be air-dried.
What Are the Advantages and Disadvantages of Fine Needle Aspiration Cytology?
The need for FNAC in oral cancer detection is mainly because of its advantages of accuracy, detection by well-structured pathology, safety procedure, and minimal trauma which makes it a reliable alternative technique to biopsy.
Also in this technique, the operator can perform a re-aspiration almost immediately because of its minimal invasive potential. Detection of oral pathologies through FNAC may help the operator and the patient gain an accurate insight into the confirmatory diagnosis of the oral condition. It also helps the dental operator plan surgical or nonsurgical procedures with respect to the nature of the oral lesion such as non-neoplastic, inflammatory, or metastatic lesions or tumors. The common oral lesions subjected to FNAC occur in the floor of the mouth, tongue, tonsils, palate, salivary glands, or posterior pharyngeal walls.
The main drawback of FNAC is that a smear cytopathological examination can evaluate whether the cells are malignant, but is not able to determine the type of the tissues.
To conclude, fine needle aspiration cytology is an extremely reliable modern technique used for not just the detection of neoplastic tumors of the head and neck, but can also be used for detecting intraoral lesions. Oral FNAC is preferred over conventional biopsy for preliminary diagnostics due to its minimal invasiveness even though with a limited drawback of less sensitivity and specificity.