Fine-needle aspiration cytology of salivary gland tumours: a 10-year retrospective analysis

The Value of Ultrasound-guided Core Needle Biopsy in Differentiating Benign from Malignant Salivary Gland Lesions

Purpose

In recent years, core needle biopsy (CNB) technique has received much attention, being used as alternative method of tissue sampling for surgical biopsy of salivary gland tumors (SGTs). The present study aimed to evaluate the value of CNB in differentiating benign from malignant SGTs.

Materials and methods

Patients with suspected benign or malignant SGTs in imaging were enrolled in this study. All core needle biopsies were performed under ultrasound guidance, i.e. ultrasound-guided Core Needle Biopsy (USCNB). Histological examination of the specimen after surgical excision was regarded as gold standard test and set as reference standard to assess USCNB accuracy for discriminating between ultrasound-visible benign and malignant SGTs.

Results

Based on USCNB results, from 36 participants (14 women and 22 men) with SGTs, 44.4% of detected tumors were benign and 55.5% were malignant. Twenty-two patients underwent surgery and postoperative specimen histological examination showed that 59% of excised lesions were benign and 41% were malignant. USCNB and surgical biopsy (SB) findings were completely compatible for 21 patients. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of USCNB were 100% in differentiating malignant from benign lesions.

Conclusion

USCNB is a valuable and accurate method of diagnosis with high sensitivity and specificity in distinguishing benign from malignant ultrasound-visible SGTs.

Histogram analysis of ultrasonographic images in the differentiation of benign and malignant parotid gland tumors

OBJECTIVE

We evaluated the diagnostic value of histogram analysis (HA) using ultrasonographic (US) images for differentiation among pleomorphic adenoma (PA), adenolymphoma (AL), and malignant tumors (MT) of the parotid gland.

STUDY DESIGN

Preoperative US images of 48 patients with PA, 39 patients with AL, and 17 patients with MT were retrospectively analyzed for gray-scale histograms. Nine first-order texture features derived from histograms of the tumors were compared. Area under the receiver operating characteristic curve (AUC) was used to evaluate the diagnostic performance of texture features. The Youden index maximum exponent was used to calculate sensitivity and specificity.

RESULTS

Statistically significant differences were discovered in Mean and Skewness HA values between PA and AL (P<0.001), and in Mean values between AL and MT (P<0.001). However, comparison of PA and MT showed no statistically significant differences (P>0.01). Excellent discrimination was detected between PA and AL (AUC=0.802), and between AL and MT (AUC=0.822). The combination of Mean plus Skewness improved discrimination between PA and AL (AUC=0.823) with sensitivity values reaching 1.00. However, Mean plus Skewness applied to differentiate PA from AL and Mean values applied to distinguish AL and MT resulted in low specificity, indicating many false positive interpretations.

CONCLUSIONS

Histogram analysis is useful for differentiating PA from AL and AL from MT but not PA from MT.

Diagnostic performance of qualitative and radiomics approach to parotid gland tumors: which is the added benefit of texture analysis?

OBJECTIVE

To investigate whether MRI-based texture analysis improves diagnostic performance for the diagnosis of parotid gland tumors compared to conventional radiological approach.

METHODS

Patients with parotid gland tumors who underwent salivary glands MRI between 2008 and 2019 were retrospectively selected. MRI analysis included a qualitative assessment by two radiologists (one of which subspecialized on head and neck imaging), and texture analysis on various sequences. Diagnostic performances including sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC) of qualitative features, radiologists' diagnosis, and radiomic models were evaluated.

RESULTS

Final study cohort included 57 patients with 74 tumors (27 pleomorphic adenomas, 40 Warthin tumors, 8 malignant tumors). Sensitivity, specificity, and AUROC for the diagnosis of malignancy were 75%, 97% and 0.860 for non-subspecialized radiologist, 100%, 94% and 0.970 for subspecialized radiologist and 57.2%, 93.4%, and 0.927 using a MRI radiomics model obtained combining texture analysis on various MRI sequences. Sensitivity, specificity, and AUROC for the differential diagnosis between pleomorphic adenoma and Warthin tumors were 81.5%, 70%, and 0.757 for non-subspecialized radiologist, 81.5%, 95% and 0.882 for subspecialized radiologist and 70.8%, 82.5%, and 0.808 using a MRI radiomics model based on texture analysis of T₂ weighted sequence. A combined radiomics model obtained with all MRI sequences yielded a sensitivity of 91.5% for the diagnosis of pleomorphic adenoma.

CONCLUSION

MRI qualitative radiologist assessment outperforms radiomic analysis for the diagnosis of malignancy. MRI predictive radiomics models improves the diagnostic performance of non-subspecialized radiologist for the differential diagnosis between pleomorphic adenoma and Warthin tumor, achieving similar performance to the subspecialized radiologist.

ADVANCES IN KNOWLEDGE

Radiologists outperform radiomic analysis for the diagnosis of malignant parotid gland tumors, with some MRI qualitative features such as ill-defined margins, perineural spread, invasion of adjacent structures and enlarged lymph nodes being highly specific for malignancy. A radiomic model based on texture analysis of T₂ weighted images yields higher specificity for the diagnosis of pleomorphic adenoma compared to a radiologist non-subspecialized in head and neck radiology, thus minimizing false-positive pleomorphic adenoma diagnosis rate and reducing unnecessary surgical complications.

The Role of Preoperative Computed Tomography Radiomics in Distinguishing Benign and Malignant Tumors of the Parotid Gland

Objective

This study aimed to develop and validate an integrated prediction model based on clinicoradiological data and computed tomography (CT)-radiomics for differentiating between benign and malignant parotid gland (PG) tumors via multicentre cohorts.

Materials and Methods

A cohort of 87 PG tumor patients from hospital #1 who were diagnosed between January 2017 and January 2020 were used for prediction model training. A total of 378 radiomic features were extracted from a single tumor region of interest (ROI) of each patient on each phase of CT images. Imaging features were extracted from plain CT and contrast-enhanced CT (CECT) images. After dimensionality reduction, a radiomics signature was constructed. A combination model was constructed by incorporating the rad-score and CT radiological features. An independent group of 38 patients from hospital #2 was used to validate the prediction models. The model performances were evaluated by receiver operating characteristic (ROC) curve analysis, and decision curve analysis (DCA) was used to evaluate the clinical effectiveness of the models. The radiomics signature model was constructed and the rad-score was calculated based on selected imaging features from plain CT and CECT images.

Results

Analysis of variance and multivariable logistic regression analysis showed that location, lymph node metastases, and rad-score were independent predictors of tumor malignant status. The ROC curves showed that the accuracy of the support vector machine (SVM)-based prediction model, radiomics signature, location and lymph node status in the training set was 0.854, 0.772, 0.679, and 0.632, respectively; specificity was 0.869, 0.878, 0.734, and 0.773; and sensitivity was 0.731, 0.808, 0.723, and 0.742. In the test set, the accuracy was 0.835, 0.771, 0.653, and 0.608, respectively; the specificity was 0.741, 0.889, 0.852, and 0.812; and the sensitivity was 0.818, 0.790, 0.731, and 0.716.

Conclusions

The combination model based on the radiomics signature and CT radiological features is capable of evaluating the malignancy of PG tumors and can help clinicians guide clinical tumor management.

Next-generation sequencing assay in salivary gland cytology: A pilot study

BACKGROUND

Preoperative diagnosis of salivary gland tumors (SGTs) by fine-needle aspiration (FNA) cytology is challenging. Next-generation sequencing (NGS)-based assays for somatic mutations have a great advantage in that a large number of genes can be analyzed simultaneously. Although NGS may have an enormous diagnostic potential in cytology, to our knowledge, the significance of NGS in SGT cytology remains to be clarified.

METHODS

In this pilot study, we retrospectively examined 32 frozen SGT samples obtained at surgery (14 malignant and 18 benign). After the stored frozen tumor tissues were thawed, aspirate samples were obtained using 22-gauge needles and subjected to smear tumor samples and to DNA extraction for an NGS assay employing the Illumina AmpliSeq Cancer Hotspot Panel v2. The results were correlated to preoperative cytological diagnosis.

RESULTS

The preoperative diagnoses obtained by FNA cytology included 23 negative lesions (no malignancy in 6 and benign tumor in 17) and nine positive lesions (suspicious for malignancy in 4 and malignancy in five), providing a sensitivity and a specificity of 9/14 (64%) and 18/18 (100%), respectively. The NGS assay detected somatic mutations in 10/14 malignant and 1/18 benign SGT cases, providing a sensitivity and a specificity of 71% and 94%, respectively.

CONCLUSION

The NGS assay may be helpful for detecting the malignant potential in SGT cases and can be used as an ancillary test for SGT cytology.

Improving the diagnosis of common parotid tumors via the combination of CT image biomarkers and clinical parameters

Background

Our study aims to develop and validate diagnostic models of the common parotid tumors based on whole-volume CT textural image biomarkers (IBMs) in combination with clinical parameters at a single institution.

Methods

The study cohort was composed of 51 pleomorphic adenoma (PA) patients and 42 Warthin tumor (WT) patients. Clinical parameters and conventional image features were scored retrospectively and textural IBMs were extracted from CT images of arterial phase. Independent-samples t test or Chi-square test was used for evaluating the significance of the difference among clinical parameters, conventional CT image features, and textural IBMs. The diagnostic performance of univariate model and multivariate model was evaluated via receiver operating characteristic (ROC) curve and area under ROC curve (AUC).

Results

Significant differences were found in clinical parameters (age, gender, disease duration, smoking), conventional image features (site, maximum diameter, time-density curve, peripheral vessels sign) and textural IBMs (mean, uniformity, energy, entropy) between PA group and WT group (P<0.05). ROC analysis showed that clinical parameter (age) and quantitative textural IBMs (mean, energy, entropy) were able to categorize the patients into PA group and WT group, with the AUC of 0.784, 0.902, 0.910, 0.805, respectively. When IBMs were added in clinical model, the multivariate models including age-mean and age-energy performed significantly better than the univariate models with the improved AUC of 0.940, 0.944, respectively (P<0.001).

Conclusions

Both clinical parameter and CT textural IBMs can be used for the preoperative, noninvasive diagnosis of parotid PA and WT. The diagnostic performance of textural IBM model was obviously better than that of clinical model and conventional image model in this study. While the multivariate model consisted of clinical parameter and textural IBM had the optimal diagnostic performance, which would contribute to the better selection of individualized surgery program.

Cytologic grading of primary malignant salivary gland tumors: A blinded review by an international panel

BACKGROUND

Fine needle aspiration (FNA) is commonly used for the preoperative evaluation of salivary gland tumors. Tumor grade is a key factor influencing clinical management of salivary gland carcinomas (SGCs). To assess the ability to grade nonbasaloid SGCs in FNA specimens, an international panel of cytopathologists convened to review and score SGC cases.

METHODS

The study cohort included 61 cases of primary SGC from the pathology archives of 3 tertiary medical centers. Cases from 2005 to 2016 were selected, scanned, and digitized. Nineteen cytopathologists blinded to the histologic diagnosis reviewed the digitized cytology slides and graded them as low, high, or indeterminate. The panelists' results were then compared to the tumor grades based on histopathologic examination of the corresponding resection specimens.

RESULTS

All but 2 of the 19 (89.5%) expert panelists review more than 20 salivary gland FNAs per year; 16 (84.2%) of the panelists work at academic medical centers, and 13 (68.4%) have more than 10 years' experience. Participants had an overall accuracy of 89.4% in the grading of SGC cases, with 90.2% and 88.3% for low- and high-grade SGC, respectively. Acinic cell carcinoma and mucoepidermoid carcinoma had the highest degree of accuracy, while epithelial-myoepithelial carcinoma and salivary duct carcinoma had the lowest degree of accuracy. As expected, the intermediate-grade SGC cases showed the greatest variability (high-grade, 42.1%; low-grade, 37.5%, indeterminate, 20.4%).

CONCLUSION

This study confirms the high accuracy of cytomorphologic grading of primary SGC by FNA as low- or high-grade. However, caution should be exercised when a grade cannot be confidently assigned.

A retrospective comparison of salivary gland fine needle aspiration reporting with the Milan system for reporting salivary gland cytology

BACKGROUND

Fine needle aspiration (FNA) is a routine sampling method in the diagnostic work up of salivary gland lesions. Despite universal use, no standardised classification existed for the cytopathological reporting of such entities until recently. The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) aims to standardise the reporting of these lesions, offering risk of malignancy rates and clinical management recommendations.

METHODS

We retrospectively applied MSRSGC to cases reported over a 5-year period. Salivary FNA specimens were reclassified according to the MSRSGC as (I) non-diagnostic, (II) non-neoplastic, (III) atypia of undetermined significance (AUS), (IV) benign neoplasm and salivary gland neoplasm of uncertain malignant potential, (V) suspicious for malignancy, and (VI) malignant. Cases with surgical resections were documented and risk of malignancy calculated for each group, where possible. We compared our outcomes with similar studies performed since publication of the Milan criteria.

RESULTS

In total, 192 specimens were reassigned as non-diagnostic (n = 30), non-neoplastic (n = 31), AUS (n = 1), benign neoplasm (n = 97) and salivary gland neoplasm of uncertain malignant potential (n = 4), suspicious for malignancy (n = 3), and malignant (n = 26). There were 73 surgical resections. Our calculated risk of malignancy was within the proposed MSRSGC rates for the non-diagnostic, benign neoplasm and malignant groups. One AUS case did not undergo surgery. Benign and malignant sensitivities and specificities for the original reporting categories were 88.24% and 95.72%, and 100% and 95.45% for the MSRSGC, respectively.

CONCLUSION

Salivary gland FNA has high diagnostic accuracy and the MSRSGC offers standardised reporting and assistance in the stratification of cases. This may improve communication between pathologists and clinicians with improved outcomes for patients.

A retrospective 3-year study of salivary gland FNAC with categorisation using the Milan reporting system

INTRODUCTION

To assess our practice using the recently developed standardised classification system designated The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) and to ascertain the rates of malignancy for each category by means of a retrospective study.

METHODS

All salivary gland FNAC samples received between 1 January 2013 and 31 December 2015 were retrospectively assigned a diagnostic category code from the MSRSGC. Cytology results were correlated with subsequent histology (where available), and clinical and radiological follow up.

RESULTS

A total of 287 salivary gland FNA samples were received from 272 patients. The specimens were classified as non-diagnostic (21.3%), non-neoplastic (22%), atypia of undetermined significance (2.4%), neoplasm benign (36.9%), neoplasm of uncertain malignant potential (5.2%), suspicious for malignancy (1.7%) and malignant (10.5%; low grade 1.4% and high grade 9.1%). Histological and clinical/radiological follow up was available for 138 (48.1%) specimens, clinical/radiological follow up only for 145 (50.5%) and no follow up for the remaining four (1.4%) samples. The risk of malignancy for each category was non-diagnostic (8.5%), non-neoplastic (1.6%), atypia of undetermined significance (0%), neoplasm benign (1.9%), neoplasm of uncertain malignant potential (26.7%), suspicious for malignancy (100%) and malignant (100%).

CONCLUSIONS

The MSRSGC appears to be a useful tool to guide clinical management and provide an indication of possible risk of malignancy. We favour implementing use of these categories in our reporting practice with a future re-evaluation to assess maintenance of service quality as well as the clinical utility of this reporting system.

Use of fluorescent in-situ hybridisation in salivary gland cytology: A powerful diagnostic tool

OBJECTIVE

Salivary gland cytology is challenging because it includes a diversity of lesions and a wide spectra of tumours. Recently, it has been reported that many types of salivary gland tumours have specific molecular diagnostic signatures that could be identified by fluorescent in-situ hybridisation (FISH). The aim of the present study was to demonstrate the feasibility and efficiency of FISH on routine cytological salivary gland smears.

METHODS

FISH was conducted on 37 cytological salivary gland smears from 34 patients. According to the cytological diagnosis suspected, MECT1/MAML2 gene fusion and rearrangements of PLAG1, MYB, or ETV6 were analysed. The presence and percentages of cells that had gene rearrangements were evaluated. Results were compared with the histological surgical samples, available from 26 patients.

RESULTS

The PLAG1 rearrangement was observed in 12/20 (60%) cases of pleomorphic adenoma. MECT1/MAML2 gene fusion was observed in 1:2 mucoepidermoid carcinomas but was not observed in five other tumours (two pleomorphic adenomas, one Warthin's tumour, one mammary analogue secretory carcinoma [MASC] and one cystic tumour). MYB rearrangement was observed in 4/4 adenoid cystic carcinomas. ETV6-gene splitting identified one MASC.

CONCLUSION

Overall, FISH had a specificity of 100% and a sensitivity of 66.7%. When FISH and cytological analyses were combined, the overall sensitivity was increased to 93.3%. It can thus be concluded that when the FISH analysis is positive, the extent of surgery could be determined with confidence pre-operatively without needing a diagnosis from a frozen section.

Role of Fine-Needle Aspiration Biopsy in the Management of Salivary Gland Masses

Objective

Fine-needle aspiration biopsy (FNAB) is widely used in the management of salivary gland masses. Its main advantage is its ability to differentiate benign from malignant disease. In this study, we aimed to evaluate the diagnostic ability of FNAB in salivary gland masses.

Methods

The records of patients who had undergone FNAB before parotidectomy or submandibular gland excision between 2005 and 2013 were retrospectively analyzed. FNAB results were classified as negative, positive, suspicious for malignancy, and non-diagnostic. Preoperative FNAB results were compared with definitive histopathological results. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of FNAB results were calculated.

Results

A total of 285 patients were enrolled. Among them, 230 (80.7%) had parotid gland and 55 (19.3%) had submandibular gland masses. Following a definitive histopathological examination, the most common benign tumor was pleomorphic adenoma (52.6%), whereas malignant tumors were mucoepidermoid carcinoma (2%) and squamous cell carcinoma (2%). The sensitivity, specificity, PPV, NPV and accuracy of FNAB results were 76.9%, 95.4%, 75%, 95.9%, and 92.6%, respectively. The rate of a suspicious cytology was 5.2% (15 patients) and that of a non-diagnostic cytology was 8.8% (25 patients).

Conclusion

FNAB is a safe and simple diagnostic tool for the diagnosis of salivary gland masses and has a relatively high sensitivity and specificity. It may provide valuable information for patient counselling and surgical planning. The major drawbacks include a lower sensitivity than specificity and a relatively high rate of non-diagnostic results.

Diagnostic role of fine needle aspiration cytology (FNAC) in the evaluation of salivary gland swelling: an institutional experience

Background

Fine needle aspiration cytology (FNAC) is a cytodiagnostic method based on morphologic findings of individual and small group of cells aspirated using a fine needle. The aim of the present study is to evaluate the spectrum of salivary gland lesions in our setting and to assess the diagnostic accuracy of FNAC for salivary gland lesions.

Methods

The study involved 187 cases of parotid and submandibular swellings of patients who underwent FNAC at our institution. Thirty one (31) patients with a FNAC diagnosis of neoplastic lesion subsequently underwent excision biopsies. The results of FNAC and final histology were compared and accuracy of FNAC was determined.

Results

Mean age of patients was 42 (±21) years and male to female ratio was 1:1. Chronic sialadenitis was the most common non-neoplastic lesion (33.8%) followed by acute and chronic sialadenitis (29.7%) and chronic granulomatous inflammation (27.0%). Pleomorphic adenoma was the most common benign neoplasm and non-Hodgkin’s lymphoma was the most common malignant lesion (38.9%) followed by acinic cell (27.8%) and adenoid cystic carcinoma (16.7%). Total 31 patients subsequently underwent surgical excision, out of which 21 were benign and 9 were malignant, 20 cases (64.5%) were of pleomorphic adenoma, 3 cases (9.6%) of acinic cell carcinoma, 2 cases (6.4%) each of warthin tumor, adenoid cystic carcinoma and non-hodgkin lymphoma and 1 case (3.2%) each of mucoepidermoid carcinoma and mucinous adenocarcinoma. The overall accuracy of FNAC in our study was found to be 83.8% with 77.7% sensitivity and 86.3%, specificity. The revised sensitivity and specificity after adjusting verification bias were 68.5% and 91% respectively. False negative diagnosis was rendered in mucoepidermoid carcinoma and acinic cell carcinoma whereas false positive diagnosis was given in cases of pleomorphic adenoma.

Conclusion

We found a good concordance between FNAC and histology, however pleomorphic adenoma may impart a diagnostic challenge when inadequately aspirated and therefore we advice either immunohistochemical studies (if cell block material is available) or repeat aspiration in difficult cases.

Accuracy of Core Needle Biopsy Versus Fine Needle Aspiration Cytology for Diagnosing Salivary Gland Tumors

BACKGROUND

Core needle biopsy is a relatively new technique used to diagnose salivary gland lesions, and its role in comparison with fine needle aspiration cytology needs to be refined.

METHODS

We compared the results of 228 ultrasound-guided core needle biopsy and 371 fine needle aspiration procedures performed on major salivary gland tumors with their postoperative histological diagnoses.

RESULTS

Core needle biopsy resulted in significantly higher sensitivity and more accurate tumor subtyping, especially for malignant tumors, than fine needle aspiration. No patient developed major complications after core needle biopsy.

CONCLUSIONS

We recommend ultrasoundguided core needle biopsy as the primary diagnostic tool for the preoperative evaluation of patients with salivary gland lesions, especially when malignancy is suspected.

Preoperative assessment of salivary gland neoplasms with fine needle aspiration cytology and echography: a retrospective analysis of 357 cases

Fine-needle aspiration cytology (FNAC) is a minimally invasive procedure usually well tolerated, easy to perform, quick, cheap and easy to repeat in case of doubts or non-diagnostic results. Echography is also a fast, cheap and non-invasive tool; however, the role of FNAC and echography in the diagnosis of salivary gland pathology is not universally recognised. Three hundred and fifty-seven patients with a cytological diagnosis at FNAC, and 247 of these who were also studied with echography, were enrolled for this retrospective study. The final histopathological diagnoses, obtained after surgery, were then compared to the preoperative FNAC diagnoses and echographic findings. From the analysis of our data, the overall FNAC specificity resulted 93 percent, sensitivity 83 percent, and diagnostic accuracy 92 percent. Echography sensibility was 57.1 percent specificity 98.2 percent, while positive and negative predictive value were respectively 80 percent and 94.8 percent. While echography can be useful in order to provide a better characterization of salivary gland lesions, FNAC can then be considered a safe diagnostic tool with reliable sensitivity and specificity for the assessment of salivary gland pathology and thus for selecting patients and indicating the best surgical treatment.

Verification bias in diagnostic accuracy studies for fine- and core needle biopsy of salivary gland lesions in otolaryngology journals: a systematic review and analysis

BACKGROUND

Diagnostic test accuracy (DTA) studies for needle biopsy are frequently published in otolaryngology journals, but this body of literature has not been assessed for verification bias.

METHODS

We conducted a systematic review of DTA studies on needle biopsy of salivary gland lesions appearing in otolaryngology journals. Studies were assessed by 2 reviewers for verification bias.

RESULTS

We identified 95 DTA studies for needle biopsy of salivary gland lesions. Eighty-one studies (84%) had verification bias. Five of the biased studies provided sufficient data to estimate the extent of bias. Verification bias was associated with an overestimate of sensitivity and an underestimate of specificity. Studies on core needle biopsy (CNB) had a lower rate of verification bias than fine-needle aspiration (FNA) studies.

CONCLUSION

Verification bias is common in DTA studies of needle biopsy for salivary gland lesions published in ear, nose, and throat (ENT) journals. Such studies overestimated sensitivity and underestimated specificity.

Salivary gland tumors: A 20-year review of clinical diagnostic accuracy at a single center

Obtaining reliable pre-operative diagnosis is crucial in planning treatment for patients with salivary gland tumors. The purpose of this study was to evaluate the accuracy of pre-operative clinical diagnosis of salivary gland tumors managed at a single tertiary university hospital over a period of 20 years. A retrospective analysis of the period between 1992 and 2011 was carried out to review the cases of patients with salivary gland tumors. A total of 101 patients were enrolled and general data were described. Clinical diagnosis was compared with the final pathological diagnosis to reveal the clinical diagnostic accuracy. Of the parotid and submandibular gland tumors, 86 and 67% were benign, respectively. The clinical diagnostic accuracies for diagnosis of parotid tumors as benign or malignant were 100 and 57%, respectively. The clinical diagnostic accuracies for diagnosis of submandibular tumors as benign or malignant were 67%. Therefore, the overall clinical judgment of benign and malignant tumors in the submandibular gland is unreliable. The accuracy for a parotid tumor to be clinically interpreted as benign was 100%. While it is difficult to draw any conclusion for non-parotid gland tumors, surgical intervention should be recommended in patients with parotid tumors clinically suspected to be malignant, and all submandibular, sublingual and minor salivary gland tumors.

Fine needle aspiration cytology of benign salivary gland tumors with myoepithelial cell participation: an institutional experience of 575 cases

OBJECTIVE

The aim of this study was to evaluate the diagnostic accuracy of fine needle aspiration (FNA) cytology of benign salivary gland tumors with myoepithelial cell participation, namely, pleomorphic adenoma, basal cell adenoma and myoepithelioma, at a single institution over a period of 10 years.

STUDY DESIGN

This study was based on 575 cytologic and matching histological samples (534 pleomorphic adenomas, 26 basal cell adenomas and 15 myoepitheliomas).

RESULTS

In most cases (393/534) of pleomorphic adenoma, a precise diagnosis was given. However, only 2 cases of basal cell adenoma and 1 case of myoepithelioma were diagnosed definitively. Descriptive diagnosis, instead of a definite diagnosis, was rendered in 16.9% of pleomorphic adenomas, 53.8% of basal cell adenomas and 40.0% of myoepitheliomas. Among all cases, the possibility of malignancy was raised in 5.2% of pleomorphic adenomas, 15.4% of basal cell adenomas and 20.0% of myoepitheliomas with a variable degree of suspicion.

CONCLUSION

In some cases, the distinction between these three neoplasms remains difficult in that all exhibit some degree of myoepithelial participation. However, FNA showed a high diagnostic accuracy in diagnosing benign salivary tumors with myoepithelial differentiation, and triage into this category provides sufficient information for clinicians to make treatment decisions.

Diagnostic difficulties in fine needle aspiration of benign salivary glandular lesions

Background

The diagnostic accuracy of fine needle aspiration cytology (FNAC) of salivary lesions is relatively high, but cytologic interpretation might be confusing if the sample is lacking typical cytologic features.

Methods

There were 77 cases of benign salivary lesions, consisting of pleomorphic adenoma (PA) in 61 cases, Warthin's tumor (WT) in 12 cases, and other benign lesions in 4 cases. The causes of the discrepancies between the FNAC and the histologic diagnoses were evaluated.

Results

Major discrepancies were noted in 4 of the 61 PA cases, and in 1 of 12 WT cases. The causes of the major discrepancies were a mislabeled site in 1 PA and 1 WT case, and an interpretation error in 3 PA cases. Minor discrepancies were more common in the WT cases (7 of 12 cases) than in the PA cases (11 of 61 cases). The causes of the minor discrepancies were a mislabeled site in 1 PA and 1 WT case, an inadequate sample in 7 PA and 2 WT cases, a lack of typical cytomorphology in 2 PA and 2 WT cases, and an interpretation error in 1 PA and 2 WT cases.

Conclusions

To increase the diagnostic accuracy in the benign salivary lesions, recognition of both characteristic and less typical cytomorphology is needed.

Salivary gland carcinomas

INTRODUCTION

Salivary gland carcinomas are rare tumours of heterogeneous morphology that require distinctive surgical and adjuvant therapy.

METHODS

Relevant studies were electronically searched in PubMed and reviewed for innovative and important information.

RESULTS

Recent insights in genetic alterations like chromosomal aberrations, expression of receptor tyrosine kinases, malfunction of tumour suppressor genes or DNA promoter methylations increased the knowledge about aetiology and pathogenesis. New histological subtypes are recognised, and a three-tiered grading system seems reasonable. Ultrasound remains the basic diagnostic imaging procedure. New developments comprise the diffusion-weighed magnetic resonance imaging, while fluorodeoxyglucose positron emission tomography/computed tomography shows good diagnostic accuracy in detecting distant metastases and local recurrence. Fine-needle aspiration cytology helps in differentiating a neoplasia from a non-neoplastic lesion while being unreliable in recognising malignancy. In contrast, additional core needle biopsy and/or intraoperative frozen section diagnosis increase the accuracy in diagnosing a malignant lesion. Conservative parotid surgery with nerve monitoring remains state-of-the-art. Free flaps or musculoaponeurotic flaps are proposed for prevention of Frey's syndrome. As parotid cancer often shows skip metastases, complete ipsilateral neck dissection (level I-V) is indicated particularly in high-grade lesions. Adjuvant radio(chemo)therapy increases local tumour control, whereas overall survival is not necessarily improved. Current results of systemic chemotherapy or targeted therapy in advanced tumour stages are disappointing.

CONCLUSION

Despite several developments, salivary gland carcinomas remain a heterogeneous group of tumours challenging both pathologists and clinicians.