Abstract : Fine Needle Aspiration Cytology (FNAC) is a widely used diagnostic tool for evaluating head and neck lesions. Its simplicity, cost-effectiveness, minimal invasiveness, and rapid results make it an essential initial diagnostic modality, especially in resource-limited settings. FNAC aids in distinguishing between benign and malignant lesions and assists in planning management strategies. This review summarizes the indications, techniques, diagnostic accuracy, advantages, limitations, and recent advances in FNAC use across various head and neck sites including lymph nodes, thyroid, salivary glands, and soft tissue masses.
Introduction : Lesions in the head and neck region encompass a wide spectrum of pathologies, including inflammatory, infectious, benign neoplasms, and malignancies. Given the complex anatomy and functional importance of this region, a rapid and accurate diagnosis is essential. Fine Needle Aspiration Cytology (FNAC) has become a preferred first-line diagnostic approach for evaluating palpable masses. It provides critical cytological information that guides the clinician’s decision-making regarding further imaging, biopsy, or surgical intervention.
Review of Literature : This review is based on a comprehensive search of the literature using databases such as PubMed, Google Scholar, and Scopus. Keywords used included “FNAC,” “head and neck,” “thyroid,” “salivary gland,” and “cytology diagnosis.” Articles from the last 15 years were prioritized. Review articles, meta-analyses, original research papers, and WHO guidelines were reviewed. Emphasis was placed on sensitivity, specificity, diagnostic utility, and clinical impact of FNAC.
Review
1. FNAC Technique
FNAC is typically performed using a 22–25 gauge needle with or without aspiration, depending on the lesion's nature. Ultrasound guidance is used for deep-seated or non-palpable lesions. Smears are prepared and stained with May-Grünwald Giemsa or Papanicolaou stain for cytological evaluation.
2. FNAC in Thyroid Lesions
Thyroid nodules are one of the most common indications for FNAC. The Bethesda System for Reporting Thyroid Cytopathology standardizes reporting and stratifies malignancy risk. FNAC reduces unnecessary surgeries in benign lesions and directs prompt management for malignancies.
3. FNAC in Lymphadenopathy
FNAC effectively differentiates reactive, granulomatous (e.g., tuberculosis), metastatic, and lymphomatous lymphadenopathy. It is particularly valuable in regions with high tuberculosis prevalence. Immunocytochemistry and molecular studies can supplement cytology in lymphoma cases.
4. FNAC in Salivary Gland Lesions
Salivary gland FNAC assists in distinguishing benign from malignant tumors. While some overlap in cytological features exists, FNAC can effectively categorize pleomorphic adenomas, Warthin’s tumors, and mucoepidermoid carcinomas. Limitations include low sensitivity in cystic or low-grade malignancies.
5. FNAC in Soft Tissue and Skin Lesions
Superficial soft tissue masses such as lipomas, epidermoid cysts, or skin adnexal tumors can be evaluated cytologically. FNAC aids in initial categorization but may require histopathology for definitive diagnosis.
6. Diagnostic Accuracy
FNAC has shown sensitivity ranging from 85–95% and specificity of 90–100% in various head and neck lesions. Accuracy depends on operator skill, lesion type, and availability of ancillary tests.
Discussion : 7. Advantages and Limitations
Advantages:
Rapid diagnosis
Outpatient procedure
Cost-effective
Low complication rate
Limitations:
Sampling errors
Inconclusive results in cystic/necrotic lesions
Limited ability to grade or subtype certain malignancies
8. Recent Advances
Advances in image-guided FNAC, liquid-based cytology, and ancillary techniques like immunocytochemistry and molecular testing have expanded the diagnostic potential of FNAC, especially in challenging cases.
Conclusion : FNAC is a cornerstone in the diagnostic evaluation of head and neck masses. It offers a safe, reliable, and cost-effective approach, enabling early diagnosis and guiding management. Its diagnostic accuracy improves with ultrasound guidance and integration of ancillary techniques. Despite certain limitations, FNAC remains indispensable in modern head and neck pathology practice.
References :
1. Layfield LJ. Fine-needle aspiration in the diagnosis of head and neck lesions. Pathology (Phila). 2001;33(4):273–283.
2. Baloch ZW, Livolsi VA. Diagnostic problems in thyroid FNAs: an institutional experience. Diagn Cytopathol. 2000;22(2):87–91.
3. Stewart CJ, et al. FNAC of salivary gland tumors: a review. Acta Cytol. 2000;44(5):747–757.
4. Nasuti JF, et al. Diagnostic value of FNAC in lymphadenopathy. Diagn Cytopathol. 2000;23(5):287–291.
5. Ogilvie JB, et al. The impact of thyroid FNAC. Am J Surg. 2006;191(3):311–316.
6. Kini SR. Guides to Clinical Aspiration Biopsy: Thyroid. Lippincott Williams & Wilkins; 2008.
7. Frable WJ. Thin-needle aspiration biopsy: complications. Laryngoscope. 1992;102(4):375–378.
8. Goyal S, et al. Role of FNAC in diagnosis of head and neck lesions: a retrospective study. Indian J Otolaryngol Head Neck Surg. 2013;65(1):42–45.
9. Yu GH, et al. Utility of FNAC in pediatric head and neck lesions. Cancer Cytopathol. 2001;93(1):40–45.
10. Lemos M, et al. Ancillary testing in FNAC of salivary gland tumors. Arch Pathol Lab Med. 2011;135(4):490–498.