You are in: eMedicine Specialties > Otolaryngology and Facial Plastic Surgery > SALIVARY GLANDS Salivary Glands, Fine-Needle AspirationArticle Last Updated: Jun 29, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 10
  Author: Philip E Zapanta, MD, Assistant Professor of Surgery, Associate Director of Otolaryngology Residency Program, Division of Otolaryngology-Head and Neck Surgery, George Washington University Medical Center; Consulting Staff, Division of Otolaryngology-Head and Neck Surgery, Medical Faculty Associates Philip E Zapanta is a member of the following medical societies: American Academy of Otolaryngic Allergy, American Academy of Otolaryngology-Head and Neck Surgery, and Christian Medical & Dental Society Coauthor(s): Sung Kim, MS, George Washington University School of Medicine and Health Sciences; John M Truelson, MD, FACS, Chairman, Division of Head and Neck Surgery, Associate Professor, Department of Otorhinolaryngology, University of Texas Southwestern Medical Center at Dallas; S Tunc Gokaslan, MD, Assistant Professor, Department of Pathology, University of Texas Southwestern Medical Center Editors: Clark A Rosen, MD, Director, University of Pittsburgh Voice Center; Associate Professor, Department of Otolaryngology and Communication Science and Disorders, University of Pittsburgh School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Dominique Dorion, MD, MSc, FRCSC, Program Director and Division Chair, Professor of Surgery, Division of Otolaryngology, University of Sherbrooke, Canada; Christopher L Slack, MD, Otolaryngology-Facial Plastic Surgery, Private Practice, Associated Coastal ENT; Medical Director, Treasure Coast Sleep Disorders; Arlen D Meyers, MD, MBA, Professor, Department of Otolaryngology-Head and Neck Surgery, University of Colorado School of Medicine Author and Editor Disclosure Synonyms and related keywords: FNA, fine needle aspiration, biopsy salivary gland tumors, fine-needle aspiration biopsy, fine needle aspiration biopsy, FNAB INTRODUCTIONSection 2 of 10
  Major salivary glands are easily accessible; therefore, they are optimal targets for fine-needle aspiration (FNA). This technique has been used for decades in Europe, but it is still controversial in the United States. The large numbers of benign and malignant tumors that can originate in the glands, as well as the lack of cytological markers to accurately diagnose the various tumors, often foster uncertainty in FNA diagnosis of salivary gland masses. Therefore, the primary challenge of FNA is differentiating benign from malignant disease and then differentiating the various malignancies. FROZEN SECTION VERSUS FNASection 3 of 10
Although several papers indicate that the sensitivity and specificity of FNA and frozen section of salivary glands are similar, malignant salivary gland lesions have always been difficult to classify with FNA alone. Frozen section diagnosis should be more effective than FNA in diagnosing salivary gland tumors; unfortunately, it has a less-than-perfect track record. In a 1987 report, Conley notes that pathologists change their frozen section diagnosis in 10% of cases. In a study of 256 salivary tumors, errors in judging malignant versus benign tumors with frozen section diagnosis occurred in 5% of cases. In 4 cases (1.6%), a malignant frozen section diagnosis was changed to benign with permanent sections. This is the most important error because it could result in more radical resection than necessary. The authors reiterated the well-known notion that radical surgery is imprudent based on the frozen section findings alone. In a similar study of 75 patients (14 malignant), no benign lesions were over diagnosed as malignant by frozen section examination. In 4 cases, a benign diagnosis on frozen section analysis was revised to malignant with permanent section examination. Although overall diagnostic accuracy was only 85%, no patient underwent unnecessary surgery, and 4 patients benefited from more radical surgery based on the frozen section diagnosis. This study shows that exceptions can be made to the rule that radical salivary gland surgery should never be performed on the basis of frozen pathology alone. While frozen section has limitations, it makes the 2-dimensional architecture of the lesion available for examination. FNA would be expected to offer an even lower accuracy because this advantage is not possible in cytologic examination. In large academic centers, FNA can correctly diagnose the cell type in 61-94% (Siewert, 2004) of cases and can correctly differentiate between malignant and benign tumors in 81-98% of cases (Seethala, 2005). A study of 220 cases of parotid gland FNA with histological follow-up was conducted to compare relative accuracies of both FNA and frozen section. Frozen section was performed in 57 of these cases. Sensitivity, specificity, and accuracy for FNA when diagnostic were 86%, 92%, and 90% respectively. Frozen section was able to change 4 malignant diagnoses by FNA to benign and provide diagnosis for 5 of the 12 non-diagnostic FNAs. The sensitivity, specificity, and accuracy of frozen section were 77%, 100%, and 88%. The authors conclude FNA and frozen section have similar accuracies. FNA is more sensitive, and frozen section is more specific; therefore, both techniques are complementary to each other in the diagnosis of salivary gland lesions (Seethala, 2005). ADVANTAGES OF FNASection 4 of 10
TECHNIQUESection 5 of 10
Depending on the clinical situation, the cytopathologist, surgeon, or radiologist may perform the FNA. Identification of the nodule is essential to the successful aspiration. Deep lesions that are less than 1 cm in diameter are best aspirated under ultrasonographic or CT scanning guidance. The skin is cleaned with an alcohol swab. A 25- or 23-gauge needle is used on a plastic disposable 10- or 20-mL syringe attached to a plastic or metal holder. The nodule is immobilized between the fingers, and the needle tip is rapidly directed through the skin into the nodule. Once the needle enters the mass, the needle is continuously aspirated while the needle is rapidly moved in and out to obtain the sample. Suction is then relieved, and the needle is withdrawn and detached from the syringe. Air is aspirated, and the material is expelled on glass slides. The material is gently but rapidly smeared on the slides and immediately dipped in alcohol fixative. Some of the slides can be left to air dry for Diff-Quick staining and rapid evaluation. The fixed material is stained by Papanicolaou or hematoxylin-eosin stains which both are excellent for nuclear detail. If necessary, a cellblock is prepared from cells entrapped in a blood clot or tiny tissue particles obtained by FNA. A cellblock enables the pathologist to examine the tissue similarly to a biopsy, and multiple sections can be obtained from paraffin-embedded material for special studies (immunohistochemistry). The syringe is rinsed into a container with formalin for adequate fixation of cellblock material (Suen, 1990). COMPLICATIONSSection 6 of 10
FNAs are safely performed worldwide. The complications of salivary gland FNA are rare, but 6 potential complications exist, including the following:
CONTRAINDICATIONSSection 7 of 10
The general contraindication to FNA include the following:
DIAGNOSISSection 8 of 10
FNA accuracy Before making a definitive treatment decision, combining FNA results with other data is prudent clinical practice. A typical example is a cytologic diagnosis of a lymphoepithelial cyst. The cyst is common in patients who have immunodeficiency virus (HIV); these patients tend to have bilateral lymphoepithelial cysts, and their findings are typical on CT scanning. Typically, these patients can be managed by serial examinations and occasional serial therapeutic aspiration. Lymphomas may also be accurately diagnosed if adequate tissue can be obtained for flow cytometry. A patient with an FNA diagnosis of Warthin tumor may be best served by having a technetium scan confirmation without surgery if significant medical contraindications to surgery exist. Recurrent tumors may also be accurately diagnosed using FNA. Some situations exist where a benign FNA cytologic appearance should be viewed with suspicion. If the mass is painful, appears to be invading surrounding structures, or co-exists with an ipsilateral facial nerve palsy and the FNA is benign, then the mass may be malignant despite a benign cytologic appearance. While FNA is very accurate, situations exist where the final permanent pathology differs from the FNA result. The following statistics demonstrate the high level of sensitivity and specificity of FNA in salivary gland lesions. In 6249 cases of primary salivary gland lesions, FNA biopsies revealed 4642 benign lesions and 1607 malignant lesions. The overall diagnostic accuracy of FNA was 48%. Sensitivity for detecting malignant and benign tumors was 73% and 91% respectively. Results of FNA biopsy are as follows (Interlaboratory Comparison Program in Nongynecologic Cytopathology [NCG] data from 1999-2003):
Benign lesions that were most often misdiagnosed as malignant were monomorphic adenoma (53% false positive rate), intraparotid lymph node (36%), oncocytoma (18%), and granulomatous sialadenitis (10%). The malignant lesions that were most often misdiagnosed as benign were lymphoma (57%), acinic cell carcinoma (49%), low-grade mucoepidermoid carcinoma (43%), and adenoid cystic carcinoma (33%) (Hughes, 2005). Because of the referral pattern at these institutions, the distribution of the salivary gland lesions summarized here does not necessarily reflect the true incidence in the general population. Pitfalls of diagnosis in salivary gland FNA
Role of special techniques Some tumors have unique characteristics that can be discovered using special techniques. While these are helpful, they are not always completely diagnostic.
CONCLUSIONSection 9 of 10
FNA of the salivary glands is a safe and reliable technique in the primary diagnosis and follow-up of patients. This technique is used with great success in Europe and is gaining increased popularity in the United States as the experience of pathologists and confidence of clinicians increase. With the application of special techniques, FNA can be a very important part of clinical decision-making and preoperative counseling in most cases. As always, the patient's overall status must be assessed, and an individual treatment plan must be created in each case. While patients with high cardiac risk may be best served by observation given a benign FNA diagnosis, young healthy patients may require surgical intervention regardless of a negative FNA finding. A negative FNA finding alone should not prevent surgical intervention when it is otherwise clinically indicated. Similarly, FNA alone cannot dictate the extent of surgery because that judgment is based on tumor location and patient status. Sacrifice of the facial nerve or other structures is generally best guided by findings at surgery rather than mindless obedience to preoperative dictums, as noted by Spiro: "Facial nerve preservation is ill advised when a parotid tumor has to be transected to spare the nerve. This rule applies even when the tumor is benign." This is not to say that decisions are always easy. On the contrary, making on-the-spot decisions with unusual tumor types that cannot be diagnosed with certainty at the time of surgery is often difficult. Ultimately, diagnosis and treatment depend upon the experience of the pathologist and surgeon when dealing with anything less than permanent section diagnosis. In a center that has a relatively large volume and a pathologist with a great deal of experience and interest in salivary gland tumors, FNA and/or frozen section diagnosis may be adequate to make preoperative and operative decisions. REFERENCESSection 10 of 10
Salivary Glands, Fine-Needle Aspiration excerpt Article Last Updated: Jun 29, 2006 |
