Pitfalls in Salivary Gland Fine-Needle Aspiration Cytology

International Journal of Pathology; 2009; 7(2): 61-65

original article

Noor ul Aan and Ashok Kumar Tanwani
Department of Pathology, Pakistan Institute of Medical Sciences

Introduction: Fine needle aspiration cytology (FNAC) of salivary gland lesion is being increasingly used. Major salivary glands and some minor salivary glands are optimal targets for fine-needle aspiration (FNA). In some instances the final histology of these lesions differs from the FNA result. 
Objective: To determine the diagnostic accuracy of FNAC in salivary gland lesions and identify the salivary gland FNA cases having discordant histological diagnosis so that most common diagnostic pitfalls can be avoided.
Material and Methods: In Pathology department, PIMS, 61 salivary gland FNAC cases from Jan 2008 to Sep 2009 were retrospectively reviewed to identify the cytological characteristics that may have contributed to this discrepancy.
Results: 31 were males and age ranges from 04-76 years (mean 38.84 ± 14). 25(43.1%) were diagnosed non-neoplastic, 31(55.1%) were rendered benign while 02 (3.44%) were malignant on cytology. Positive predictive value of FNAC was 100% and negative predictive value was 91.4%. 08 FNAC cases show discordant diagnosis in specific typing of the lesion. 6/8 cases were misdiagnosed as pleomorphic adenoma. The most common missed diagnosis was mucoepidermoid carcinoma.
Conclusion: Pleomorphic adenoma and mucoepidermoid carcinoma are common in occurrence and create problems in diagnosis. Experience cytopathologist should review all the cytology slides
Keywords: FNAC, histopathology, salivary glands lesions

Introduction

Fine needle aspiration cytology (FNAC) is being increasingly used in the diagnosis of salivary gland lesions. Major salivary glands and some minor salivary glands are easily accessible; therefore they are optimal targets for Fine Needle Aspiration (FNA). Different studies reveal high sensitivity and specificity of FNA with few pitfalls1-3. It has some edge over an incisional biopsy and frozen section. FNAC is a simple, quick, useful and reliable procedure. Wide sampling of the lump is possible. This procedure takes only 5-10 minutes and result could be available after 15-20 minutes. In majority of cases FNA is helpful in differentiating between benign and malignant lesions. However due to diverse morphological patterns and overlapping features between benign and malignant lesions, distinction between two is not very easy in every case. Thus at times it becomes very challenging and difficult to give precise diagnoses. The aim of the present study is to discuss pitfalls and problems in salivary gland lesions and try to find out possible solutions.

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