**2. FNAC: a vital diagnostic tool in salivary gland pathology**

FNAC is easy, minimally invasive, cost effective technique which provides a rapid initial preoperative diagnosis of SG tumours and has an impact on subsequent management and treatment [11]. The sensitivity and specificity of FNAC in diagnosing SG tumours is 85–100% and 90–100% respectively. The aspirated material obtained through FNAC can also be utilized for special staining such as Periodic acid-Schiff (PAS), Periodic acid-Schiff with diastase (PAS-D), Mucicarmine, Phosphotungstic acid-haematoxylin (PTAH), Acid fast bacilli (AFB) and Gram staining for further evaluation and diagnosis. PAS-D and mucicarmine are particularly useful for highlighting mucin containing cells in challenging cases of low-grade mucoepidermoid carcinoma (MEC). Similarly, PTAH stain can be applied on paraffin-embedded cell block preparation for identification oncocytic cells in challenging diagnosis of tumours with oncocytic differentiation. The cell blocks can also be utilized for Immunohistochemistry (IHC) for demonstrating epithelial and myoepithelial components in diagnosis of challenging tumours. The epithelial cells are positive for immunohistochemical markers such as cytokeratin and epithelial membrane antigen (EMA) and the myoepithelial cells show positivity for smooth muscle actin (SMA), calponin, p63 and S-100. Further, the aspirated material can also be used for microbiological culture, immunophenotyping and molecular analysis for confirming the cytological diagnosis. While the FNAC of palpable lesions in major SGs is relatively easy, the FNAC of intraoral SGs is challenging as many times aspirates are not cellular as these intraoral sites are often difficult to approach and sometimes inaccessible [10–12]. In such cases, radiological-guided FNAC may be advised for better yield of aspirates for subsequent cytological diagnosis. Also, while performing FNAC, there are chances of complications such as hemorrhage, nerve pain and damage and infection. There can be post FNAC induced changes in tissue such as squamous metaplastic changes, inflammation, granulation tissue formation and sometimes infarction, which may interfere with subsequent histological diagnosis. Therefore, familiarity with key cytological features with recognition of the subtle cytomorphological changes in cells is crucial for overcoming barriers and making a correct diagnosis.
