Fine needle aspiration cytology for parotid neoplasms: risk of malignancy through inconclusive results and lower grade tumors

Current surgical management of malignant parotid tumors

PURPOSE OF REVIEW

Surgical treatment of parotid cancer presents challenges due to the rarity of the disease, the histologic heterogeneity, and the complex regional anatomy. Recently published international guidelines contain recommendations for surgical management of the primary tumor and the neck lymph nodes, but still allow both T and N to be managed in different ways. This review summarizes the remaining areas of discussion.

RECENT FINDINGS

The reference treatment for parotid cancer is total parotidectomy; however, for low-grade, low-stage tumors a superficial parotidectomy may be sufficient. The cN+ neck requires a comprehensive neck dissection; for cN0 multiple valuable options remain. Frozen section analysis on level II nodes can guide the extent of neck dissection. The definition of 'clear margins' remains debated; close margins in low-grade tumors appear to be acceptable, positive margins always require additional treatment.

SUMMARY

A thorough understanding of the guidelines, fine-tuned if needed based on accurate preoperative workup and intraoperative surgeon's decision-making will provide the best outcome for the patient with parotid cancer.

Ultrasound-enhanced fine-needle biopsy improves tissue yield in head and neck tumors ex vivo

Current needle biopsy techniques, i.e., fine-needle aspiration biopsy (FNAB) and core needle biopsy (CNB), are widely utilized in cancer diagnostics but have certain shortcomings. The limited yield of diagnostic cellular material and the low sensitivity to detect various types of malignancies are well-known problems with FNAB. In contrast, CNB provides a histological sample but is typically more labor-intensive to obtain. Ultrasound-enhanced FNAB (USeFNAB) represents a novel approach that utilizes an ultrasonically oscillating fine-needle tip to enhance tissue yield. This study aims to assess the feasibility of employing USeFNAB in head and neck tumors in an ex vivo setting. Parotid gland tumors (PGT; N = 10) and neck lymph nodes of patients with head and neck cancer (HNC; N = 10) were resected and biopsied using three techniques: USeFNAB, FNAB, and CNB which served as a comparative method. The samples obtained were weighed and the yield and quality of the tissue fragments were evaluated by pathologists. Immunohistochemical staining was performed to determine whether USeFNAB had any impact on the staining characteristics of the sample. The findings showed that USeFNAB, at a 0.5 W power level, produced a tissue sample (mass) that was 1.9 times higher in the PGT group, and 4.6 times higher in the HNC group compared to FNAB. The quality of the sample obtained via USeFNAB was comparable to that of FNAB. USeFNAB did not alter the immunohistochemical staining characteristics. Overall, USeFNAB appears to be a promising tool for improving the tissue yield of fine-needle biopsy and enhancing diagnostic accuracy.

Ultrasound-Enhanced Fine-Needle Biopsy Improves Yield in Human Epithelial and Lymphoid Tissue

OBJECTIVE

Needle biopsy is a common technique used to obtain cell and tissue samples for diagnostics. Currently, two biopsy methods are widely used: (i) fine-needle aspiration biopsy (FNAB) and (ii) core needle biopsy (CNB). However, these methods have limitations. Recently, we developed ultrasound-enhanced fine-needle aspiration biopsy (USeFNAB), which employs a needle that flexurally oscillates at an ultrasonic frequency of ∼32 kHz. The needle motion contributes to increased tissue collection while preserving cells and tissue constructs for pathological assessment. Previously, USeFNAB has been investigated only in ex vivo animal tissue. The present study was aimed at determining the feasibility of using USeFNAB in human epithelial and lymphoid tissue.

METHODS

Needle biopsy samples were acquired using FNAB, CNB and USeFNAB on ex vivo human tonsils (N = 10). The tissue yield and quality were quantified by weight measurement and blinded pathologists' assessments. The biopsy methods were then compared.

RESULTS

The results revealed sample mass increases of, on average, 2.3- and 5.4-fold with USeFNAB compared with the state-of-the-art FNAB and CNB, respectively. The quality of tissue fragments collected by USeFNAB was equivalent to that collected by the state-of-the-art methods in terms of morphology and immunohistochemical stainings made from cell blocks as judged by pathologists.

CONCLUSION

Our study indicates that USeFNAB is a promising method that could improve tissue yield to ensure sufficient material for ancillary histochemical and molecular studies for diagnostic pathology, thereby potentially increasing diagnostic accuracy.

An ultrasound-based histogram analysis model for prediction of tumour stroma ratio in pleomorphic adenoma of the salivary gland

OBJECTIVES

Preoperative identification of different stromal subtypes of pleomorphic adenoma (PA) of the salivary gland is crucial for making treatment decisions. We aimed to develop and validate a model based on histogram analysis (HA) of ultrasound (US) images for predicting tumour stroma ratio (TSR) in salivary gland PA.

METHODS

A total of 219 PA patients were divided into low-TSR (stroma-low) and high-TSR (stroma-high) groups and enrolled in a training cohort (n = 151) and a validation cohort (n = 68). The least absolute shrinkage and selection operator regression algorithm was used to screen the most optimal clinical, US, and HA features. The selected features were entered into multivariable logistic regression analyses for further selection of independent predictors. Different models, including the nomogram model, the clinic-US (Clin + US) model, and the HA model, were built based on independent predictors using logistic regression. The performance levels of the models were evaluated and validated on the training and validation cohorts.

RESULTS

Lesion size, shape, cystic areas, vascularity, HA_mean, and HA_skewness were identified as independent predictors for constructing the nomogram model. The nomogram model incorporating the clinical, US, and HA features achieved areas under the curve of 0.839 and 0.852 in the training and validation cohorts, respectively, demonstrating good predictive performance and calibration. Decision curve analysis and clinical impact curves further confirmed its clinical usefulness.

CONCLUSIONS

The nomogram model we developed offers a practical tool for preoperative TSR prediction in PA, potentially enhancing clinical decision-making.

[Indications for fine-needle aspiration and core needle biopsy for diagnosis of salivary gland tumors]

BACKGROUND

Salivary gland malignancies are rare neoplasms of the head and neck area. Preoperative clinical and imaging assessment of salivary gland masses is challenging. However, preoperative identification of malignancy is crucial for further treatment and for the course of the disease.

OBJECTIVE

This article presents the advantages and disadvantages of fine-needle aspiration cytology (FNAC) and core needle biopsy (CNB). Additionally, the sensitivity and specificity of both methods for predicting malignancy were analyzed. Furthermore, it is discussed which procedure is suitable for the diagnostic work-up of salivary gland tumors.

MATERIALS AND METHODS

This current article summarizes important and recent studies in the field of the diagnostic work-up for salivary gland lesions, with discussion of original articles, metanalyses, and systematic reviews concerning FNAC and CNB.

RESULTS

The sensitivity and specificity of the predictive ability of FNAC for malignancy is described at between 70.0-80.0% and 87.5-97.9%. The pooled sensitivity and specificity for CNB were 92.0-98.0% and 95.0-100.0%, respectively. Tumor cell seeding or facial nerve palsy are very rare complications of both procedures.

CONCLUSION

If malignancy is suspected based on clinical examination or imaging, FNAC or CNB should be performed. FNAC is easy to perform; however, an onsite cytologist is necessary. CNB has a higher sensitivity for routine diagnosis of malignancy; tumor typing and grading is facilitated by preserving the histological architecture. In conclusion, CNB is the procedure of choice in the diagnostic work-up for suspected malignant salivary gland tumors.

Assessing the Agreement Between Preoperative Fine-Needle Aspiration Cytology (FNAC) Done for Major Salivary Gland Neoplasm When Reported by Head and Neck Pathologists and Non-head and Neck Pathologists with Its Final Histopathology

The preoperative FNA is an important investigation in the workup of a salivary gland pathology. A preoperative diagnosis is important to plan management and counsel patients accordingly. In this study, we aimed to assess the agreement between the preoperative FNA and the final histopathology report when reported by a head and neck and a non-head and neck pathologist. All patients with major salivary gland neoplasm having undergone a preoperative FNA before surgery from January 2012 to December 2019 at our hospital were included in the study. Analysis was done to check for concordance between head and neck and non-head and neck pathologists of the preoperative FNA and final histopathology. Three hundred and twenty-five patients were included in the study. The preoperative FNA could identify the tumour as benign or malignant in the majority (n = 228, 70.1%). The agreement between the preoperative FNA, frozen section diagnosis and the reporting of grade in the frozen section and the final HPR was slightly better with the head and neck pathologist (kappa = 0.429, kappa = 0.698 and kappa = 0.257), respectively, than with the non-head and neck pathologist (kappa = 0.387, kappa = 0.519 and kappa = 0.158), all of which was statistically significant (p < 0.001). The diagnosis made with the preoperative FNA and reporting in the frozen section had a fair agreement with the final histopathology when reported by a head and neck pathologist in comparison to a non-head and neck pathologist.

Ultrasound-guided core biopsy in the diagnosis of parotid neoplasia: an overview and update with a review of the literature

OBJECTIVE

Accurate diagnosis of parotid neoplasia is a key to determine the most appropriate patient management choice, including the need for surgery. This review provides an update of the literature on current practice and outcomes of parotid tissue sampling techniques, with an emphasis on ultrasound-guided core biopsy (USCB) and comparison with fine needle aspiration cytology (FNAC).

METHODS

A literature review of EMBASE, Medline, PubMed and Google Scholar was conducted.

RESULTS

USCB has higher sensitivity, specificity and lower non-diagnostic rates than optimized FNAC. It also has a significantly higher sensitivity for the detection of malignancy. Significant complications post-USCB are uncommon, with only one reported case of tumour seeding and no cases of permanent facial nerve dysfunction. The technique is less operator-dependent than FNAC, with less reported variation in results between institutions.

CONCLUSIONS

USCB can be considered as the optimum tool of choice for the diagnosis of parotid neoplasia. This would particularly be the case in centres utilizing FNAC with high non-diagnostic rates or reduced diagnostic accuracy when compared to USCB published data, or in centres establishing a new service.

ADVANCES IN KNOWLEDGE

An update of the role and outcomes of USCB in the diagnosis of parotid gland pathologies.Research shows that USCB preforms better than FNAC, in terms of sensitivity and specificity, particularly in the case of malignant neoplasia.Complications following USCB were found to be higher than that of FNAC; however, no long-term major complications following either method have been reported in the literature.

The importance of the patient's perspective in function-sparing parotid surgery for benign neoplasms: clinical reappraisal

Objective

Function-sparing surgery is the cornerstone for the treatment of benign parotid neoplasms. We assessed the incidences and determinants of the main postoperative complications, reappraising their influence on the patient’s quality of life (QoL).

Methods

Patients who underwent parotid surgery for benign neoplasms were reviewed (2016-2019). Parotidectomy Outcome Inventory-8 (POI-8) and condition-specific questionnaires were used to investigate the patient’s perspective.

Results

We enrolled 211 patients. Preservation of the posterior branch of the great auricular nerve (GAN) seemed to reduce early dysfunction (87% vs 96%, p = 0.053), but not the late one. Deep lobe dissection and resection of more than one parotid segment favoured first bite syndrome (FBS) and Frey’s syndrome (FS), respectively (16% vs 3%, p = 0.003; 37% vs 15%, p = 0.003). Neither GAN impairment, FBS, nor FS influenced patient QoL. Facial weakness affected 19 patients (9%), being more likely after total parotidectomy (23% vs 7%, p = 0.034). According to POI-8, QoL was mainly jeopardised by fear of revision surgery, especially in females (p= 0.005) and those experiencing early complications (p= 0.004).

Conclusions

Reappraisal of the patient’s perspective after functional parotid surgery is fundamental to tailor preoperative counselling.

Cytopathology and diagnostics of Warthin's tumour

Warthin's tumour (WT) is a benign epithelial salivary tumour, one type of salivary adenoma. Histologically, WT is structured of two components, epithelial tissue that often lines cystic formations and lymphoid tissue in the tumour stroma. FNA is a reliable diagnostic approach in the diagnosis of salivary gland lesions allowing a highly accurate categorization of benign tumour-like lesions, benign tumours and malignant tumours. In the proposed Milan reporting system of salivary gland lesions, WT is categorized in the IVA group of benign neoplasms. Accurate cytological diagnosis is straightforward when three characteristic components are present: oncocytes, either isolated or associated in clusters, lymphocytes and lymphoid cells and often an inflammatory/necrotic-like substance. Also, specific features of scintigraphy and radiological imaging contribute to the diagnosis of WT. WT is categorized according to Seifert G. et al in 4 types, depending on the proportions of the epithelial component and lymphoid stroma. Differential cytopathological and pathohistological diagnosis include other salivary gland lesions with lymphoid, oncocytic epithelial and cystic components. In some cases, such as the metaplastic WT variant, there are additional cytopathological and histological diagnostic difficulties. Moreover, bilateral, multicentric or multiple and infrequently seen extra-salivary localizations of WT are associated with further cytopathological diagnostic difficulties. Also, a rare possibility of malignant transformation of the epithelial or lymphoid component of WT as well as possible association with other primary tumours remains a challenge in accurate cytopathological and histological diagnosis of WT.

Accuracy, predictability and prognostic implications of fine-needle aspiration biopsy for parotid gland tumours: A retrospective case series

OBJECTIVE

To evaluate the precision and utility of fine-needle aspiration (FNA) in differentiating between benign and malignant parotid tumours, and the implications of FNA results on management and outcomes.

DESIGN

Retrospective case series.

SETTING

Tertiary medical centre.

PARTICIPANTS

All adults who underwent preoperative FNA, followed by postoperative histological examination, between 1986 and 2014.

MAIN OUTCOME MEASURES

Differences in clinical management and outcomes of patients with parotid masses in light of FNA results.

RESULTS

We analysed 505 samples from 485 patients. According to histopathological results, preoperative FNA successfully identified benign tumours in 89% of the cases (362/405) and only 59% of malignant tumours (59/100). Overall sensitivity and specificity of FNA in distinguishing between different subtypes of benign lesions were 80% and 99%, respectively, whereas positive predictive value (PPV) and negative predictive value (NPV) were 85% and 98%. Moreover, malignant lesions subtyping had high false-positive and false-negative rates with sensitivity, specificity, PPV and NPV of 44%, 100%, 75% and 99%, respectively. Additionally, when FNA falsely classified malignant tumours as benign, surgeries were inappropriately delayed and the durations of surgeries and hospitalisations were shorter, compared to true malignant FNA results. Interestingly, survival was not affected in falsely benign lesions that were mostly low-grade, conversely non-diagnostic FNA for malignant tumours resulted in decreased survival.

CONCLUSIONS

Our findings highlight the limitations of FNA as a decision-making tool in preoperative evaluation of parotid masses. Clinicians should take into account that FNA is inaccurate for identifying specific subtypes of malignant lesions, which may eventually delay treatment and influence outcome.

A multicenter validation of the revised version of the Milan system for reporting salivary gland cytology (MSRSGC)

INTRODUCTION

Fine-needle aspiration cytology (FNAC) is a basic step in the diagnosis of salivary gland tumors that have a wide variety of histological types. The recent Milan system for reporting salivary gland cytopathology (MSRSGC) can correlate the risk of malignancy with precise cytological features. A revised version was recently proposed to improve the surgical relevance and facilitate uniform management.

MATERIAL AND METHODS

A multicenter study retrospectively used the original and revised MSRSGC criteria to classify a series of patients who received surgery after FNAC.

RESULTS

We enrolled 503 patients from three tertiary centers. The risk of malignancy for the MSRSGC resulted 19.5% in cat. I, 14.3% in cat. II, 17.6% in cat. III, 3.6% in cat. IVa, 24.6% in cat. IVb, 66.7% in cat. V, and 96.8% in cat. VI. The results from the revised MSRSGC were consistent with the original values.

CONCLUSION

The MSRSGC is a promising classification system. In our opinion, the revised version of the MSRSGC supplements FNAC with some crucial clinical information and can better identify the appropriate treatment in each category.