Diagnostic reliability of FNAC for salivary gland swellings: a comparative study

A prospective study was conducted to see the sensitivity, specificity, and accuracy of fine needle aspiration cytology (FNAC) for 100 salivary gland swellings in comparison with biopsy. These randomized samples were submitted and reported at the department of pathology, Allama Iqbal Medical College, Lahore. The male to female ratio was 1:1.5. Ages of the patients ranged from 8.5 to 58 years with mean age 33.39 +/- 12.37 years. Maximum number of lesions was found in age group between 21 and 40 years. Parotid gland was involved in 68%, submandibular gland in 30%, and minor salivary glands in 2% patients. Sublingual gland was not involved in any of our subjects. There were 14% cases of non-neoplastic lesions and 86% cases of neoplastic lesions on biopsy. Non-neoplastic lesions included 12 cases of inflammations (three cases of granulomatous inflammation and nine cases of nonspecific chronic inflammation) and two cases of inclusion cysts. Among neoplastic lesions, biopsy revealed 68 cases of benign neoplasia and 18 cases of malignant neoplasia. Non-neoplastic lesions did not show any difference in diagnosis by both techniques. FNAC misdiagnosed four malignant and one benign lesion. Sensitivity, specificity, positive predictive value, and negative predictive value of FNAC for benign neoplastic lesions were 98.52, 87.05, 94.36, and 96.55%, respectively, whereas for malignant neoplastic lesions they were 77.77, 98.78, 93.33, and 95.29%, respectively. In conclusion, FNAC is found to be a highly sensitive and specific technique for diagnosis of most of salivary gland swellings, except for malignant neoplastic lesions where its sensitivity is intermediate. We strongly recommend that FNAC should be adopted as an initial investigation for all salivary gland swellings.