Diagnostic Accuracy of Benign Salivary Gland Aspiration Cytology - A Study with Histopathological Correlation

BACKGROUND Fine needle aspiration cytology (FNAC) is commonly used as a safe and minimally invasive diagnostic test in benign salivary gland lesions. Nevertheless, the capacity of aspiration cytology in diagnosing benign lesions in the salivary gland is still disputed because accurate tumour typing is dependent on the quality and yield of the aspirate, as well as the competence of the cytopathologist. We aim to assess the precision of fine needle aspirate in the pre-operative diagnosis of benign salivary gland lesions and compare it with the histopathological findings. METHODS This is a longitudinal study conducted among 45 patients with preoperative cytological diagnosis of benign salivary gland lesions, who were followed-up till surgery with subsequent histopathological examination in Government Medical College, Thrissur, from 1 st January 2013 to 30th June 2015. RESULTS Among the benign neoplasms, 29 out of 30 cases of pleomorphic adenoma were confirmed on histopathology and one was basal cell adenoma. Out of nine cases of Warthin’s tumour, only seven were confirmed by histopathology. Of the remaining two, one was found to be salivary duct carcinoma showing the typical comedo necrosis and the other was found to be low grade mucoepidermoid carcinoma. So, these two cases were found to be false negative. The statistical analysis showed an overall diagnostic accuracy of 95.5 % for benign salivary gland lesions. CONCLUSIONS FNAC is a minimally invasive technique useful in salivary gland lesions. In nonneoplastic lesions surgery can be avoided and in neoplasms appropriate surgery can be planned. An accurate cytological diagnosis is often possible but may sometimes require the expertise of the cytopathology and use of ancillary techniques KEYWORDS Salivary Gland, Fine Needle Aspiration Cytology, Benign Tumours, Pleomorphic Adenoma, Warthin’s Tumour, Mucoepidermoid Carcinoma, Salivary Duct Carcinoma