Evidence of lymphangiogenesis in Warthin's tumor of the parotid gland

Pathogenesis of Warthin's Tumor: Neoplastic or Non-Neoplastic?

Warthin's tumor is the second most frequent neoplasm next to pleomorphic adenoma in the salivary gland, mostly in the parotid gland. The epithelial cells constituting a tumor are characterized by the presence of mitochondria that undergo structural and functional changes, resulting in the development of oncocytes. In addition to containing epithelial cells, Warthin's tumors contain abundant lymphocytes with lymph follicles (germinal centers) that are surrounded by epithelial cells. The pathogenesis of Warthin's tumor is not fully understood, and several hypotheses have been proposed. The risk factors for the development of Warthin's tumor, which predominantly occurs in males, include aging, smoking, and radiation exposure. Recently, it has been reported that chronic inflammation and aging cells promote the growth of Warthin's tumor. Several reports regarding the origin of the tumor have suggested that (1) Warthin's tumor is an IgG4-related disease, (2) epithelial cells that compose Warthin's tumor accumulate mitochondria, and (3) Warthin's tumor is a metaplastic lesion in the lymph nodes. It is possible that the pathogenesis of Warthin's tumor includes mitochondrial metabolic abnormalities, accumulation of aged cells, chronic inflammation, and senescence-associated secretory phenotype (SASP). In this short review, we propose that DNA damage, metabolic dysfunction of mitochondria, senescent cells, SASP, human papillomavirus, and IgG4 may be involved in the development of Warthin's tumor.

Long-Term Outcomes of Radiofrequency Ablation for Treatment of Cystic Warthin Tumors versus Solid Warthin Tumors

Background: To describe the long-term outcomes of radiofrequency ablation (RFA) of parotid Warthin tumors that have different consistencies and locations. Methods: We reviewed ten patients with Warthin tumors undergoing RFA treatment from 2016 to 2019. The mean follow-up was 24.3 ± 13.1 months (range 7–42 months). Results: RFA was performed on 11 tumors in ten patients. Cystic tumors (n = 4) had better volume reduction ratios (VRR) than solid tumors (n = 7) at month one and month six, following RFA (77.9% vs. 47.3%, 95.1% vs. 80.6%, respectively, p = 0.003). Tumors in both superficial lobes and deep lobes (n = 7) were larger than tumors in superficial lobes alone (n = 4), though there was no difference in VRR after treatment. All residual tumors were found in superficial lobes. There was no increase in residual tumor size. Every patient showed marked cosmetic improvements, with visible tumors becoming non-palpable masses. Conclusions: RFA is a safe and effective treatment for Warthin tumors, with better volume reduction in cystic tumors. Results remained satisfying over the long-term for all residual tumors found in superficial lobes, making it easier for re-intervention if necessary.

The Role of FNAC in the Diagnosis and Management of Warthin Tumour: Analysis of 74 Cases

Introduction  After pleomorphic adenoma, Warthin tumor gets its popularity as the second most common benign neoplasm of the parotid gland. Fine-needle aspiration cytology (FNAC) is the most cost-effective and minimally-invasive way to determine the histological character of a parotid gland tumor. Objective  To determine the accuracy of FNAC in the diagnosis of Warthin Tumour. Methods  A retrospective study conducted between 2014 and 2018. Out of 243 FNACs performed for parotid lesions, a histopathological correlation was established in 74 cases to reveal the accuracy of FNAC in the diagnosis of Warthin tumor. Results  A total of 243 FNACs of parotid lesions were performed, and a histopathological correlation was established in 74 (30.4%) cases. Later on, we confirmed that 16 (21.6%) out of these 74 patients had cases of Warthin tumor. In total, 15 (20.3%) out of those 74 cases were confirmed as Warthin tumors on the initial cytology, which revealed a true positive concordance between the cytology and the final histological diagnosis; 55/74 (74%) were true negative results; on the other hand, 1/74 (1.4%) was a false negative, and 3/74 (4.1%) were false positive results. The sensitivity of the FNAC in the diagnosis of Warthin tumor was of 93%, while the specificity was of 94.8%, and the accuracy, of 94.6%. Conclusion  In the present study, FNAC had a high diagnostic accuracy, reaching 94%.

The Clinical Significance of Incidental Parotid Uptake in a PET/CT Study: A Diagnostic Algorithm

BACKGROUND

Patients diagnosed with cancer do not have sufficient clinical data for the management of incidental parotid lesions. We aimed to reveal the importance of randomized parotid lesions encountered during oncologic F-18 fluorodeoxyglucose positron emission tomography (FDG PET/CT) imaging in our clinical practice and the diagnostic algorithm of such lesions.

METHODS

We performed a database search of PET/CT records generated from 2009 to 2015 for "parotid" in reports of patients who underwent PET/CT examination for a known malignancy elsewhere, or cancer screening.

RESULTS

Incidental parotid FDG uptake on PET/CT had a prevalence of 1.1%. The incidence of parotid metastasis in our series was 36.4%, and 75% of them had malign melanoma metastasis. Of the 11 cases, 5 were of Warthin tumours, and Warthin tumours showed stronger GLUT1 expression than metastatic parotid lesions.

CONCLUSION

In patients with malignancy elsewhere, focal involvement of FDG by the parotid gland, especially if malignant melanoma or SCC is absent, should not be considered a metastatic disease without histopathologic confirmation. If parotid disease would change the patient's treatment plan and disease stage, the parotid lesion should be evaluated by additional methods, such as fine needle aspiration biopsy.

Quantification of heterogeneity to classify benign parotid tumors: a feasibility study on most frequent histotypes

Aim: To differentiate Warthin tumors (WTs) and pleomorphic adenomas (PAs) measuring heterogeneity of intravoxel incoherent motion (IVIM) and dynamic-contrast enhanced-magnetic resonance imaging biomarkers. Methods: Volumes of interest were traced on 18 WT and 18 PA in 25 patients. For each IVIM and dynamic-contrast enhanced biomarker, histogram parameters were calculated and then compared using the Wilcoxon-signed-rank test. Receiver operating characteristic curves and multivariate analysis were employed to identify the parameters and their pairs with the best accuracy. Results: Most of the biomarkers exhibited significant difference (p < 0.05) between PA and WT for histogram parameters. Time to peak median and skewness, and D* median and entropy showed the highest area under the curve. No meaningful improvement of accuracy was obtained using two features. Conclusion: IVIM and dynamic-contrast enhanced histogram descriptors may help in the classification of WT and PA.

Surgical treatment strategy in Warthin tumor of the parotid gland

Introduction

Warthin tumors are the second most common benign tumors of the parotid gland. We examined the clinical features of Warthin tumors in our hospital, and analyzed the consistency within the literatures.

Objective

The aim of this study is to analyze the clinical features of Warthin tumors in our 10-year experience of 118 Warthin tumors undergoing surgery at a single institute.

Methods

From December 2006 to December 2016, 110 patients who underwent surgical treatment for Warthin tumors were identified based on their medical records.

Results

A total of 118 parotid gland operations were performed in 110 patients. Almost 90% of Warthin tumors were found in males, and average patient age was 66.1 ± 6.1 years. The prevalence of smoking history was 89.1% (98/110). Eight patients (7.3%) had bilateral Warthin tumors. Seventy-seven lesions (65.3%) were located in the parotid tail portion, followed by 34 lesions in the superficial lobe (28.8%) and 7 lesions in the deep lobe (5.9%).

Conclusion

We determined the appropriate extent of surgery depending on the fine needle aspiration cytology and tumor location by computed tomography scans. Partial facial dysfunction after the operation was detected in 12 cases, and facial nerve function recovered within 3 months. Only one patient experienced a recurrence, and was disease free after the re-operation. We suggest that our treatment algorithm, depending on the location of tumors and the result of fine needle aspiration cytology, can be useful to determine the appropriate extent of surgery for Warthin tumors.

Warthin tumor within the superficial lobe of the parotid gland: a suggested criterion for diagnosis

The location of Warthin tumor (WT) in the parotid gland impacts the surgical approach and may be indicative of the elusive origin of this intriguing entity. Location in the deep versus superficial lobe of the gland is not directly addressed when defining WT characteristics. Our observation, of rare occurrence of deep lobe WT, if at all, led to the current investigation. The study design is cohort study. This is a retrospective chart review of all patients undergoing parotidectomy for WT in two tertiary academic referral centers: the Sheba Medical Center (SMC), Israel, and the Christiana Care (CC), Newark, Delaware, USA. 122 consecutive adult patients underwent parotidectomy for WT (72 from SMC and 50 from CC). Seventy percent were males, with a mean age of 60.6 years. Bilateral WT or multi-centric WT were found in 9.8 and 17.2% of the cases, respectively. In one case, the tumor was described as originating in the deep lobe. In all other cases, the tumor originated and was limited to the superficial lobe. 99.2% of WT originated in the superficial lobe, corresponding with the few reports directly addressing its location in the gland. The reason for the tumor to be limited almost uniformly to the superficial lobe is unknown, and could be related to the etiopathogenesis of this elusive entity. We suggest adding tumor location within the superficial lobe to the common characteristics of WT (male, smoking, and lower pole) that serve as "common criterion" while evaluating a parotid lesion.

Comparison of the blood and lymphatic microvessel density of pleomorphic adenoma and Basal cell adenoma

BACKGROUND

Pleomorphic adenoma (PA) is the most common tumor of the salivary gland, while basal cell adenoma (BCA) is an uncommon neoplasm. Blood and lymphatic vessels are crucial for tumor metabolism. The aim of this study was to compare the blood and lymphatic vascular density and vascular and endothelial growth factor (VEGF) expression in PA and BCA tumors. In addition, cell proliferation was evaluated in these tumors.

METHODS

Blood and lymphatic vessel content, VEGF expression, and cell proliferation were analyzed in 30 cases of PA and 13 cases of BCA by immu-nohistochemistry using antibodies for CD34, CD105, D2–40, VEGF, and Mcm−2.

RESULTS

Regarding CD34 and CD105 expression, PA demonstrated a high vascularity and a low number of positive vessels, respectively. D2–40-positive lymphatic vessels were mainly located in the tumor capsules, with small intratumoral lymphatic vessels observed occasionally. VEGF expression revealed a remarkably heterogeneous immunoreactivity, alternating from weak or negative to positive or intense. BCA presented significantly higher CD34, CD34, CD105, D2–40, and VEGF expression compared to PA. No significant difference was found in cell proliferation between the tumors.

CONCLUSION

Although PA and BCA are considered part of the same spectrum of differentiation, this study showed that the blood and lymphatic vascularization of these tumors is different.

Neither expression of VEGF-C/D nor lymph vessel density supports lymphatic invasion as the mechanism responsible for local spread of recurrent salivary pleomorphic adenoma

Recent research suggests that multinodular recurrent pleomorphic adenoma (PA) might result from cell migration through lymphatics. Lymphangiogenesis in malignancies is mediated by vascular endothelial growth factors C and D (VEGF-C/D). We studied the expression of VEGF-C/D in PA by immunohistochemistry as well as lymphatic vessel density (LVD). In 6 non-recurrent, 4 primary-to-recur, and 10 recurrent PAs, VEGF-C/D expression was assessed by immunohistochemistry. Staining was scored in terms of staining intensity (0 = absent to 3 = strong), and the percentage of positive tumor cells (scored as 0 (0-19 %), 1 (20-39 %), 2 (40-50 %), and 3 (60-100 %)) and a sum score were calculated. Intra- and peritumoral LVD was assessed by counting of LV after immunostaining, using the D2-40 antibody. All but one sample were VEGF-C negative. The differences in VEGF-D expression between non-recurrent, primary-to-recur, and recurrent PAs were not significant (p>0.05). VEGF-D expression did not correlate with peritumoral LVD (p>0.05). Our study revealed a significant difference between intra- and peritumoral LVD values when comparing individual and all sample groups (p=0.01). The lack of VEGF-C expression and of significant differences in VEGF-D expression and peritumoral LVD between patients with non-recurrent, primary-to-recur, and recurrent PAs does not support the lymphangiogenic local spread hypothesis

Different histological subtypes of parotid gland tumors: CT findings and diagnostic strategy

AIM: To present computed tomography (CT) findings of different histological subtypes of parotid gland masses in detail and to establish diagnostic strategy.

METHODS: From January 2009 to November 2011, 56 patients were collected through the histopathology and Picture Archiving and Communication Systems records, which revealed 5 basal cell adenoma (BCA), 16 pleomorphic adenoma (PA), 25 Warthin’s tumor (War-T), 3 Kimura’s disease (KD) and 7 parotid carcinoma (PCa) cases. All the CT images were retrospectively analyzed by two radiologists in consensus, based on their description of morphology (location, number, size, margin and fibrous capsule) and enhancement patterns of masses. In addition, the diagnostic efficiency of diagnostic strategy is tested.

RESULTS: War-T and BCA patients’ mean age was 59.9 ± 12.6 years and 58.4 ± 18.2 years; the significant difference was seen in War-T vs PA and BCA vs PA. About 40% of War-Ts presented with bilateral multifocal lesions, a higher ratio than others. Seventy two percent of War-Ts were limited to the superficial lobe, followed by BCA 60% and PA 40%. Vessel facing sign and enlarged lymph nodes were both frequent in War-T, which respectively accounts for 84% and 76% of cases. Rapid contrast enhancement and decreases were unique for War-T. BCA and PA showed obvious delayed enhancement. The diagnostic strategy of parotid gland tumor had a good diagnostic efficiency, with high accuracy, sensitivity and specificity.

CONCLUSION: Determination of the histological subtypes of parotid gland masses might be possible based on CT findings and clinical data. A diagnostic strategy with high diagnostic efficiency was established.

Vascular endothelial growth factor (VEGF) expression and microvascular density in salivary gland tumours

This study investigates whether salivary tumours with different morphology and evolution also differ in terms of neovascularization and VEGF expression and the prognostic value of the results. Surgical specimens from 45 patients - 8 pleomorphic adenomas (PA), 7 Warthin tumours (WT), 5 basal cell adenomas (BA), 6 carcinomas ex-pleomorphic adenoma (CEPA), 6 mucoepidermoid carcinomas (MEC), 5 acinic cell carcinomas (AC), 4 adenoid cystic carcinomas (ACC) and 4 adenocarcinomas not otherwise specified (ADK NOS) - were immunostained. In malignant salivary tumours, the following mean microvascular density (MVD) values were recorded (± SD = Standard Deviation): 27.61 (SD ± 2.27) in cases with CEPA, 27.08 (DS ± 7.81) in AC and 32.93 (SD ± 7.76) in ADK NOS, with lower values for MEC 24.31(SD ± 2.88) and for ACC 22.13 (SD ± 5.44). For benign tumours, an MVD of 35.71 (SD ± 2.09) was recorded in WT and lower average values in PA (MVD = 14.84; SD ± 4.86) and in BA (MVD = 23.96; SD ± 9.13). MVD did not correlate with the investigated clinicopathological parameters. The VEGF expression is significantly more important (p = 0.001) in malignant salivary tumours as compared with benign ones. The VEGF expression and the microvascularization in salivary gland tumours are important elements to be considered when formulating a diagnosis and assessing case evolutions in patients with such tumours.

Bilateral multifocal Warthin's tumors in upper neck lymph nodes. Report of a case and brief review of the literature

Cystadenolymphomas (Warthin's tumors) are the second most frequent lesions of the parotid gland. Due to their benign clinical behavior, the low rates of recurrence and malignant transformation they were classified as tumor-like lesions. In addition, a polyclonal growth of the epithelial components of the tumor could be detected. Warthin's tumors occur bilateral in 7-10%, whereas a multifocal appearance is extremely rare. Even if the pathogenesis is still unclear a heterotopia of salivary tissue during embryogenesis is the most likely explanation for the origin of these tumors in the upper neck and periparotideal region. Here we present a rare case of bilateral, multifocal, extraglandular Warthin's tumors in lymph nodes of the upper neck and give a brief review of the literature. If a primary malignancy can be excluded by a careful staging procedure prior to the operation an isolated excision of the lesions of the neck is the adequate treatment.

Expression of podoplanin in Warthin tumours

PURPOSE

Warthin tumour is the second most common benign tumour of the parotid gland. This study was designed to investigate the lymphatic vessels in Warthin tumours in an effort to understand better its pathogenesis.

MATERIALS AND METHODS

Tissue specimens of 31 patients (19 men and 11 women; mean age 57 years, median size of the tumours 2.86 cm) were analysed by means of immunohistochemistry applying the monoclonal antibody D2-40.

RESULTS

We found numerous D2-40-positive sinus-like vessels particularly at the inner layer of the capsule.

CONCLUSIONS

Since subcapsular sinuses are a major morphological feature of lymph nodes in general, the finding of podoplanin expression in the large majority of subcapsular vessels in Warthin tumours confirms the view that this tumour has its origin in regional lymph nodes.

Hyperplastic intraparotid lymph nodes with incipient Warthin's tumor presenting as a parotid tumor

Reactive follicular hyperplasia of the intraparotid lymph nodes (IPLs) forming a parotid tumor has rarely been reported, and the pathogenesis of Warthin's tumor has not been determined. A case of hyperplastic IPLs with incipient Warthin's tumors presenting as a parotid tumor is presented. A 68-year-old Japanese patient presented with a tumor of the right parotid gland, and the tumor was resected. Pathologic examination showed seven hyperplastic IPLs (3-15 mm in diameter) with follicular hyperplasia with a capsule, marginal sinuses, and high endothelial venules. Very small foci of Warthin's tumor were recognized in two of the IPLs. Non-tumorous ductules were scattered in four IPLs. Immunohistochemical studies showed that the oncocytes of the small Warthin's tumor and the ductular elements were positive for cytokeratin, but negative for carcinoembryonic antigen, vimentin, alpha-smooth muscle antigen, and S100 protein. The ki-67 labeling was 3%. CD20-positive B lymphocytes were located in the germinal center and peripheral B zone, and CD3-positive T lymphocytes in the interfollicular T zone. The present case suggests that reactive hyperplastic IPLs may form a parotid tumor, and that Warthin's tumor may develop in hyperplastic IPLs at the inception of its tumorigenesis.

Pathogenesis of lymphangiomas

Based on various hypotheses concerning lymphangiogenesis published in the literature, different putative mechanisms of lymphangioma development are discussed including failure of the lymphatic system to connect with or separate from the venous system, abnormal budding of the lymphatic system from the cardinal vein, or acquired processes such as traumata, infections, chronic inflammations, and obstructions. Increasingly, the possible influence of lymphangiogenic growth factors on the development of lymphangiomas is discussed. The proved expression of different growth factors in the endothelium of lymphangiomas leads to new hypotheses regarding the pathogenesis of lymphangiomas. Thus, further studies on the lymphangiogenesis and the development of lymphangiomas will have to clarify as to whether lymphangiomas are true malformations or neoplastic in nature.

Multifocal multi-site Warthin tumour

The unique case of a 55-year-old man with multifocal adenolymphoma (Warthin's tumour) of both parotid glands, the neck and post-nasal space is presented. Warthin tumour is almost exclusively a parotid tumour but is known to be bilateral in 7-10% of cases and multifocal in 2% of cases. Most extraglandular Warthin tumours have been located in neck lymph nodes and only a few cases have been reported from other sites. The presented case is unique in having synchronous and metachronous Warthin tumours, as well as one of the tumours being neither truly parotid, nor within a lymph node.