[Diagnostic accuracy and pitfalls in fine needle aspiration cytology of salivary glands: a study of 113 cases].

OBJECTIVE

To describe the fine needle aspiration cytology (FNAC) features of various salivary gland lesions and to analyze the respective diagnostic value and pitfalls.

METHODS

113 FNAC specimens of salivary gland lesions were reviewed and correlated with clinical and histopathologic findings.

RESULTS

The FNAC diagnostic failure (2); non-neoplastic lesions (12); benign neoplasm (82) and malignant neoplasm (17). Cytologically, the distinction between cellular pleomorphic adenoma, adenoid cystic carcinoma and basal cell adenoma could be difficult due to their overlapping morphologic features. The cytologic patterns of primary lymphoepithelial carcinoma of the parotid were indistinguishable from those of metastatic nasopharyngeal undifferentiated carcinoma. The ultimate distinction relied on clinical correlation. The three inaccurately diagnosed cases of FNAC are, as follows: reactive lymphoid hyperplasia of lymph node mistaken as non-Hodgkin lymphoma, mucoepidermoid carcinoma diagnosed as "scanty atypical cells present" and primary lymphoepithelial carcinoma mistaken as benign lymphoepithelial lesion. On the basis of FNAC, 97.4% (110 /113) were correctly depicted as benign (95/96; 99.0%) or malignant (15/17; 88.2%). Furthermore, 90.3% (102 /113) (specificity = 91.9%; 102/111) were accurately diagnosed, including 91.7% (88/96) benign lesions (specificity = 92.6% ; 88/95) and 82.4% (14/17) malignant tumors (specificity = 87.5%; 14/16).

CONCLUSIONS

FNAC is reliable in distinguishing benign and malignant salivary gland lesions. A specific cytologic diagnosis is often possible. On the other hand, due to the pitfalls in cytologic diagnosis of certain salivary gland tumors, tissue biopsy for histologic examination may be necessary.