Histologic subclassification of the cystadenolymphoma of the parotid gland. Analysis of 275 cases

Warthin's Tumour as a Parotid Gland Incidentaloma Identified by PET-CT Scan in a Large Series of Cases

Occasionally in imaging scans there are findings unrelated to the pathology for which the scan was indicated, findings that are called incidentalomas. Warthin tumors have a high glucose avidity, being one of the common incidentalomas in PET-CT scans. The aim of the present study is to analyze the frequency of occurrence of Warthin's tumor as an incidental finding in a large series of patients undergoing 18F-FDG PET-CT. Retrospective analysis of 18F-FDG PET-CT scans performed in our center during the period 2010-2021. Parotid hypermetabolic lesions were identified, as well as their SUVmax, size, smoking habit, BMI (body mass index), and otorhinolaryngology follow-up. 31,423 PET-CT-18FDG studies corresponding to 12,806 patients were analyzed. The frequency of incidentalomas at the parotid level with a diagnosis compatible with Warthin's tumor was 0.87% (n = 111). Eighty percent of the patients with incidentalomas accordant to Warthin's tumor had a history of tobacco use. The highest percentage of incidentalomas compatible with a Warthin tumor was found in patients in whom the indication for PET-CT was the study of a lung carcinoma (1.44%). Only 37% of patients with a PET-CT lesion compatible with a Warthin's tumor were referred for evaluation by the Otorhinolaryngology service. The incidence of Warthin's tumor in 18-FDG PET-CT scans in our center was 0.87%.

Molecular testing in salivary gland cytopathology: A practical overview in conjunction with the Milan system

Recently, significant advances in the molecular characterization of salivary gland neoplasms have facilitated the classification and diagnosis of specific diagnostic entities. In the highly challenging diagnostic scenario of salivary malignancies, molecular testing is increasingly being adopted in routine practice to refine the cytological diagnosis of salivary lesions. Here, we reviewed the most recent evidence in the field of salivary glands molecular cytopathology.

Surgical management of Warthin tumor: long-term follow-up of 224 patients from 2002 to 2018

PURPOSE

Warthin tumors (WT) are the second most common benign parotid gland neoplasms. They can occur as synchronous or metachronous lesions in 6-10% of cases. This study aims to compare the complication rate in 224 patients who underwent extracapsular dissection (ECD) or superficial parotidectomy (SP) for the treatment of a WT.

METHODS

This retrospective study was conducted at the Department of Maxillo-Facial Surgery at the University of Naples "Federico II" from February 2002 to December 2018 on a group of patients who underwent surgical treatment for WT. The type of surgical technique was chosen based on Quer's classification. The complications evaluated were facial nerve palsy, hematoma, Frey's syndrome, and bleeding.

RESULTS

A total of 224 patients treated from 2002 to 2018 for Warthin tumor were included in the study. Two hundred elven had solitary tumors (94.1%) and 13 had multicentric lesions (5.8%), of which 9 cases presented synchronous lesions and 4 cases presented metachronous lesions. Extracapsular dissection (ECD) was performed in 130 patients (58.3% of cases) and superficial parotidectomy (SP) in the other 94 (41.7% of cases).

CONCLUSIONS

We consider both surgical techniques as valid. In our opinion, it is essential to study each case based on Quer's Classification to obtain the best surgical outcome. Based on a lower observed rate of complications such as facial nerve palsy, Frey's syndrome, and bleeding, ECD seems to be the best option for the surgical treatment of Quer Class I lesions.

Fine needle aspiration as a diagnostic modality for Warthin tumors identified as fluorodeoxyglucose positron emission tomography/computed tomography-positive

Limited evidence exists regarding the 2-deoxy-2-[fluorine-18]-fluoro-D-glucose (FDG) avidity of Warthin tumors, the second most common benign parotid gland tumor. This study aims to clarify this aspect by analyzing patients who underwent FDG positron emission tomography/computed tomography (PET/CT) and quantifying tumor standardized uptake values (SUV). Medical records of 29 patients with fine needle aspiration (FNA)-confirmed Warthin tumors who underwent FDG-PET/CT near the diagnosis of Warthin tumor were reviewed. Key parameters included cancer history, cytologic diagnosis of Warthin tumor, maximum SUV on FDG PET/CT, and tumor localization. Among the cohort, 18 males and 11 females (average age: 67.9 years) were included. Most patients had malignant neoplasms (lung, head and neck, breast, others). One patient had synchronous liver cancer. Three individuals had bilateral Warthin tumors, and three had bifocal tumors, resulting in 35 tumors for analysis. Tumors were located in the parotid gland (28) and vicinity (7). SUVmax for the Warthin tumors ranged from 3.6 to 26.8, with an average SUVmax of 10.1. Warthin tumors exhibit significant and variable FDG accumulation, exceeding expectations and mimicking high-grade malignancies. Awareness of this phenomenon is crucial for accurate staging and timely management. In cases of positive FDG PET/CT uptake in periparotid, perimandibular, and upper jugular areas, FNA is recommended to avoid misinterpretation or delays in management.

MAML2 gene rearrangement occurs in all Warthin-like mucoepidermoid carcinoma: A reappraisal in a series of 29 cases

Background

Warthin-like Mucoepidermoid carcinoma (MEC) is a new and rare morphological variant of MEC, with only a few case reports in the literature. The clinicopathological, molecular features and bio-behaviors of Warthin-like MEC has not been studied extensively. We reappraisal all Warthin-like MEC patients diagnosed and treated at our hospital.

Methods

Patient characteristics including clinicopathological features, genetic aberrations, treatment, and prognostic information were assessed and evaluated.

Results

Twenty-nine Warthin-like MEC patients were identified, 19 patients were female (65.5 %), and 10 were male (34.5 %). The patients' age varied widely from 8 to 68 years (mean 42.3 years). Genetic aberrations of MAML2 rearrangement were detected in all Warthin-like MEC patients, which suggesting this genetic event is the unique feature of Warthin-like MEC. Twenty-five patients (86.2 %) were assessed as having a low-stage disease (I/II), and four (13.8 %) as having high-clinical stage disease (III/IV). More than half of the patients (16/29) underwent only partial sialoadenectomy; 2 patients underwent extended sialoadenectomy, and 11 patients underwent extended sialoadenectomy with cervical lymph node dissection. After a median follow-up time of 73 months (5-128 months), Twenty-eight patients were alive without recurrence at the end of the follow-up period, one patient died 1 year after surgery due to lung metastasis.

Conclusion

Our data suggested that most Warthin-like MEC exhibited mild clinicopathological course and less aggressive bio-behavior, and an aggressive bio-behavior seemed to be very rare. In addition, in the salivary gland, MAML2 rearrangement seems to be a unique molecular feature of salivary Warthin-like MEC.

A Safety and Feasibility Trial of Ultrasound-Guided Radiofrequency Ablation of Parotid Warthin's Tumor

OBJECTIVE

To determine if ultrasound-guided (USG) radiofrequency ablation (RFA) of Parotid Warthin's tumor under local anesthesia is a safe and effective procedure.

STUDY DESIGN

Safety and feasibility study.

SETTING

Tertiary academic medical center.

METHODS

This is an IDEAL phase 2a trial in a tertiary referral center. Twenty patients with Parotid Warthin's tumor were recruited. RFA was done between September and December 2021 for all 20 patients using a CoATherm AK-F200 machine with a disposable, 18G × 7 mm radiofrequency electrode. Results and follow-up statistics were compared with a historic sample of patients with parotid Warthin's tumor who underwent parotidectomy between 2019 and 2021 in the same center.

RESULTS

Nineteen patients were included in the analysis as 1 patient dropped out after 4 weeks of follow-up. The mean age for the RFA group was 67 years old with most of them being male smokers. At a median of 45 weeks (44-47 weeks) postprocedure there was a 7.48 mL (68.4%) volume reduction compared to baseline. Three patients had transient facial nerve (FN) paresis, 1 recovered within hours, and the other 2 by 12 weeks follow-up. Three patients had great auricular nerve numbness; 1 patient had infected hematoma treated in an out-patient manner. Compared to a historic cohort of parotidectomy patients for Warthin's tumor, there was no significant difference in FN paresis and other minor complications between the 2 treatment modalities.

CONCLUSION

The current analysis suggests that USG RFA of Warthin's Tumor is a safe alternative to parotidectomy with shorter operative time and length of stay.

Salivary gland pathologies: evolution in classification and association with unique genetic alterations

PURPOSE

The correct classification of salivary gland pathologies is crucial for choosing a treatment method and determining the prognosis. Better outcomes are now achievable thanks to the introduction of new therapy approaches, such as targeted therapies for malignant salivary gland tumors. To apply these in clinical routine, a clear classification of the lesions is required.

METHODS

The following review examines all changes from the first World Health Organization (WHO) Classification of salivary gland pathologies from 1972 to fifth edition from 2022. Possible developments in the diagnosis and classification of salivary gland pathology are also presented.

RESULTS

The current WHO classification is the fifth edition. With the development of new diagnostic methods, based on genetic alterations, it provides insight into the molecular basis of lesions. This has resulted in the evolution of classification, introduction of new entities and reclassification of existing ones.

CONCLUSIONS

Genetic alterations will become increasingly more significant in the identification of salivary gland pathologies in the future. These alterations will be helpful as prognostic and predictive biomarkers, and may also serve as targets for anti-cancer therapies.

Warthin Tumor of the Parotid Gland: The History of an Eponym

The eponymous history of Warthin tumor (WT) is a fascinating issue in the field of salivary gland pathology. The late decades of the nineteenth century and the turn of the century saw notable German and French contributions on WT. Especially, the seminal 1910 paper of Albrecht and Arzt of Vienna is the foundation for the current knowledge of WT. It is generally believed that prior to this pioneering study, Hildebrand of Göttingen accurately described the lesion of WT in 1895. However, the historical origins of WT appear to be unsettled, and only a few German pathologists and surgeons are aware that dating back to 1885, the first recognizable reference to WT was that by the renowned German-Swiss pathologist Zahn, whose name is eponymously associated with "Zahn infarct" and "lines of Zahn". Two noted French surgeons with a major interest in pathology, Albarrán in 1885 and Lecéne in 1908, did not contribute to the topic. Since the 1950s, a mostly American group of pathologists and surgeons gradually adopted the term WT to replace the very accurate histologic descriptor "papillary cystadenoma lymphomatosum" coined by Warthin himself in 1929. It is our opinion that from a historical viewpoint, there is no particular reason why this tumor should have been named WT.

Warthin-like mucoepidermoid carcinoma of the parotid gland: Clinicopathological observation and literature review

Warthin tumor (WT)-like mucoepidermoid carcinoma resembles the histologic pattern of WT and pathologists unaware of this possibility may misdiagnose it as WT with squamous and mucous epithelium metaplasia or WT malignant transfer into mucoepidermoid carcinoma. The present study reported a case of a 41-year-old Chinese female with a solitary mass in the left parotid gland. In this case, microscopic observation revealed prominent lymph node stroma and multiple cystic structures similar to those seen in WT. However, it lacked the two layers of oncocytic epithelial tissue characteristic of WT. Furthermore, fluorescence in situ hybridization detected MAML2 rearrangement in the case. Considering the histological findings, this case was diagnosed as WT-like mucoepidermoid carcinoma. The present case report provides pathological and clinical features to differentiate it from WT malignant transition into mucoepidermoid carcinoma, WT with squamous and mucous epithelium metaplasia and non-sebaceous lymphadenoma-like mucoepidermoid carcinoma. In conclusion, WT-like mucoepidermoid carcinoma as a special subtype of mucoepidermoid carcinoma has special histological characteristics, which required further observations and more case reports to clearly define this variant.

KRAS codon 12 mutations characterize a subset of de novo proliferating "metaplastic" Warthin tumors

Warthin tumor (WT; synonym: cystadenolymphoma) represents one of the most frequent salivary gland tumors with a frequency equaling or even outnumbering that of pleomorphic adenomas in some series. Histologically, the tumor displays tall columnar oncocytic cells, arranged into two cell-thick layers lining variably cystic glands within an organoid lymphoid stroma. Tumors with exuberant squamous metaplasia in response to FNA-induced or other types of tissue injury/infarction have been referred to as "metaplastic WTs." However, the same terminology was used for tumors with variable mucinous cell and solid or stratified epidermoid proliferations (occasionally mimicking mucoepidermoid carcinoma), although the "metaplasia concept" has never been proven for the latter. We herein investigated 22 WTs showing prominent mucoepidermoid-like or solid oncocytoma-like proliferations without prior FNA or histological evidence of infarction/ trauma using the TruSight Tumor 15 gene panel and KRAS pyrosequencing. As a control, we tested 11 conventional WTs. No statistically significant differences were observed between the two subcohorts regarding patient's age and tumor size. Six of 22 (27%) proliferating/ metaplastic WTs revealed oncogenic KRAS mutations clustering at codon 12 (exon 2), while all conventional tumors lacked these mutations. Our findings are in line with a neoplastic nature of the epidermoid/ mucoepidermoid proliferations in non-injured "metaplastic" Warthin tumors. We propose the descriptive term "de novo proliferating Warthin tumor" for this variant to distinguish it from infarcted/inflamed genuine metaplastic Warthin tumor.

The Milan System classification of Warthin tumor: A large institutional study of 124 cases highlighting cytologic features that limit definitive interpretation

BACKGROUND

Fine-needle aspiration (FNA) is highly accurate for the diagnosis of Warthin tumor (WT). However, there is a minor subset of WT cases that are more challenging to interpret. The goal of this study is to identify factors that limit definitive diagnosis of WT on FNA.

METHODS

All WT surgical specimens diagnosed during a 6.5-year study period were retrospectively identified and the preceding cytologic specimen diagnostic categories were analyzed. Of particular interest were WT cases with indeterminate or malignant interpretations. Cases that noted squamous or mucinous change in either the surgical or cytologic reports were also reviewed.

RESULTS

A total of 157 WT surgical specimens were identified, with 124 (79.0%) having prior FNAs. The distribution of cytologic diagnostic categories was 12 (9.7%) nondiagnostic, 10 (8.1%) nonneoplastic, 13 (10.5%) atypia of undetermined significance (AUS), 82 (66.1%) neoplasm: benign, 4 (3.2%) salivary gland neoplasm of uncertain malignant potential (SUMP), 2 (1.6%) suspicious for malignancy, and 1 (0.8%) malignant. Of the 20 cases in indeterminate/malignant categories, a majority noted either squamoid (9 of 20) or mucinous (2 of 20) changes. The remainder noted scant cellularity as a limiting factor to interpretation. Additionally, 27 cases mentioned squamous or mucinous change in the surgical or cytology report, with a wide spectrum of cytologic categorization including 2 (7.4%) nondiagnostic, 2 (7.4%) nonneoplastic, 7 (25.9%) AUS, 8 (29.6%) neoplasm: benign, 4 (14.8%) SUMP, 2 (7.4%) suspicious for malignancy, and 1 (3.7%) malignant.

CONCLUSIONS

This study identified 2 key causes for indeterminate or misclassification of WT on FNA: specimen hypocellularity and metaplastic changes. Recognition of the potential for squamous and mucinous metaplastic changes combined with observance of some helpful diagnostic clues such as the presence of crystalloids may aid in preventing diagnostic pitfalls.

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.

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.

Conventional, diffusion, and dynamic contrast-enhanced MRI findings for differentiating metaplastic Warthin's tumor of the parotid gland

The purpose of this study was to explore conventional, diffusion, and dynamic contrast-enhanced MRI (DCE-MRI) characteristics for differentiating metaplastic Warthin's tumor (MWT) from other tumor types of the parotid gland, including non-metaplastic Warthin's tumor (non-MWT), pleomorphic adenoma (PA), and malignant tumor (MT). A total of 178 patients with histologically proven tumors of the parotid gland, including 21 MWTs, 49 non-MWTs, 66 PAs, and 42 MTs, were enrolled in the study. Conventional MRI was performed in all patients. One hundred and fifty patients had preoperative diffusion-weighted MR imaging (DWI), and 62 patients had preoperative DCE-MRI. The differences in the conventional, DCE-MRI, and DWI records between MWTs and the other three tumor types were statistically evaluated. Compared with non-MWTs and PAs, there was a statistically significant difference in circumscription (p < 0.01). The ill-defined circumscription was more common in MWTs than non-MWTs and PAs. Compared with PAs, there was a statistically significant difference in morphology (p < 0.05). The lobulated morphology was more common in PAs than MWTs. Compared with PAs and MTs, there was a statistically significant difference in the T2 signal of the solid component (p < 0.01). The T2 moderate intensity of solid components was more common in MWTs than PAs and MTs. The solid components of PAs mostly showed hyperintense on T2-weighted imaging. Cyst/necrosis was more common in MWTs than PAs and MTs. Hyperintense of cyst/necrosis was more common in MWTs and non-MWTs. With respect to contrast enhancement, 52.4% MWTs exhibited moderate or marked enhancement, and most non-MWTs (81.6%) exhibited mild enhancement. Most PAs (84.8%) exhibited marked enhancement. The mean ADC value of MWTs (0.94 × 10-3 ± 0.11 mm2/s) was significantly lower than that of the PAs (1.60 × 10-3 ± 0.17 mm2/s) (p < 0.001). On DCE-MRI, six of eight MWTs demonstrated TIC of type B. Although MWT is rare, conventional MRI characteristics, DWI and DCE-MRI can provide useful information for differentiating MWT from other parotid mass.

Warthin Tumor Incidentally Detected on PET/CT Showing Both 68Ga-DOTANOC and 18F-FDG Uptake

ABSTRACT

A patient with moderately differentiated pancreatic neuroendocrine tumor with synchronous multifocal liver metastases was referred for further staging with PET/CT. The examinations were performed on 2 consecutive days and showed mild 68Ga-DOTANOC and intense 18F-FDG uptake in an incidental right parotid nodule. Differential diagnoses include primary or metastatic neuroendocrine tumor, malignant or benign primary parotid tumor, and intraparotid lymph node. Histology revealed characteristics of a Warthin tumor. While focal FDG uptake in Warthin tumor is frequently described, the somatostatin expression was rarely reported. This clinical case describes 68Ga-DOTANOC and 18F-FDG uptake in a parotid Warthin tumor histologically confirmed.

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%.

Aberrant Expression of Glyceraldehyde-3-Phosphate Dehydrogenase (GAPDH) in Warthin Tumors

The Warthin tumor represents the second most frequent benign tumor of the parotid gland and is characterized by the presence of oncocytes rich in structurally and functionally altered mitochondria. Next to its role in metabolism, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is also implicated in cellular mitophagy. Immunohistochemistry was carried out on Warthin tumor and normal control (parotid gland with striated ducts) tissues, using anti-GAPDH specific antibodies followed by digital image analysis. Laser capture microdissection was used to isolate the oncocytic tumor cell and normal control striated duct compartments for RNA extraction and qPCR. Warthin tumor oncocytes exhibited a markedly spotted GAPDH staining pattern exhibiting cells with cytoplasmic and nuclear, only nuclear or none GAPDH staining. A significantly lower (p < 0.0001) total GAPDH signal was detected in Warthin tumor oncocytes. Similarly, significantly lower (p < 0.005) GAPDH mRNA levels were seen in oncocytes compared with normal ductal cells. To exclude the possibility of this GAPDH staining pattern being a general feature of oncocytic neoplasms of different organs, we tested a cohort of renal oncocytoma and oncocytic chromophobe carcinoma; none showed this type of staining. The observed progressive GAPDH loss in Warthin tumor oncocytes could be implicated in the pathogenesis of Warthin tumors.

Prevalence of Lymphoid Neoplasia in a Retrospective Analysis of Warthin Tumor: A Single Institution Experience

Warthin tumor is one of the most common benign salivary gland tumors. Overt lymphoma is known to occur in the lymphoid stroma of Warthin tumor. In situ follicular neoplasia is difficult to identify in routine histologic examination of lymphoid tissue and has not been reported in association with Warthin tumor. Our objective is to determine the prevalence of overt malignant lymphoma and in situ follicular neoplasia in Warthin tumor. We conducted a retrospective histological evaluation of 89 sequential Warthin tumor cases with available slides and blocks from the years 2010-2019. Of these, 84 cases were subjected to immunohistochemical testing, while 5 cases had been previously worked up for the suspicion of lymphoma. We identified two additional cases of lymphoid neoplasia associated with Warthin tumor including small lymphocytic lymphoma/chronic lymphocytic leukemia (n = 1) and in situ follicular neoplasia (n = 1) in addition to previously reported case of follicular lymphoma included in this study. The prevalence rate of first-time detected lymphoid neoplasia in Warthin tumor is 3.4%. The prevalence rate of overt lymphoma is 2.2%, while the prevalence of in situ follicular neoplasia is 1.1%. We propose histologic criteria to identify small lymphocytic lymphoma and follicular lymphoma in Warthin tumor. These include a monotonous interfollicular expansion of small lymphocytes and germinal centers composed of a monotonous population of lymphocytes without polarity or tingible body macrophages respectively. It is very important for pathologists to perform a diligent morphological examination and perform immunohistochemistry in suspected cases to identify subtle involvement of Warthin tumor by lymphoma. In patients with involvement of Warthin tumor by in situ follicular neoplasia, concurrent lymphoma in the same tissue and other sites should be considered. Patients without overt lymphoma elsewhere likely have a low risk of progression to follicular lymphoma. The low prevalence of in situ follicular neoplasia in Warthin tumor, combined with the low rate of clinical progression to lymphoma, make routine screening of Warthin tumor for in situ follicular neoplasia unnecessary.

The significance of mucinous metaplasia in Warthin tumor: a frequent occurrence and potential pitfall

Mucinous metaplasia in Warthin tumor (WT) is a recognized phenomenon. Nevertheless, its presence can create a diagnostic challenge in the distinction from the newly proposed variant of mucoepidermoid carcinoma (MEC), Warthin-like MEC. In this study, we evaluated the significance and diagnostic relevance of mucinous metaplasia in WTs. A total of 30 WTs diagnosed based on resection specimens formed the basis of this retrospective study. Mucicarmine staining was performed to identify mucinous metaplasia, and fluorescence in situ hybridization (FISH) analysis was used to detect MAML2 gene rearrangement. After review, one MAML2 rearranged case was reclassified as Warthin-like MEC as the classic bilayered epithelium in WT was not identified. The diagnosis of WT was confirmed in the remaining 29 cases. Mucinous metaplasia was encountered in 24 WTs (83%), with 14% (4/29) having an abundant amount. We found that mucinous metaplasia correlated with tumor size (p < 0.05). Age and sex distribution were similar in WT cases with or without mucinous metaplasia. In addition, neither the presence of squamous metaplasia nor the time interval between fine-needle aspiration and surgery was related to mucinous metaplasia (p > 0.05). The MAML2 FISH analyses performed in 18 WTs with variable amounts of mucinous metaplasia were negative for rearrangement. In conclusion, mucinous metaplasia is fairly common in WTs and shows a significant correlation with tumor size. Therefore, caution should be taken to avoid overinterpretation of WT with mucinous metaplasia as MEC in cases showing the classic bilayered oncocytic lining epithelium.

Diffuse large B-cell lymphoma arising from follicular lymphoma with warthin’s tumor of the parotid gland - immunophenotypic and genetic features: A case report

BACKGROUND

Warthin’s tumor (WT) is composed of several cysts that are lined with tall, bilayered oncocytic columnar cells and lymphoid stroma. Within WT, the two components rarely transform into carcinoma or lymphoma, and when it does, carcinoma is the most common type. Approximately 28 cases of lymphoma with WT have been reported, most of which were non-Hodgkin lymphomas, and only a few cases were Hodgkin lymphomas. In the present report, we studied a case of diffuse large B cell lymphoma (DLBCL) arising from follicular lymphoma (FL) with WT in the parotid gland and its immunophenotypic and genetic features.

CASE SUMMARY

A 67-year-old man presented with a slowly enlarging right cheek mass for 12 years, and the mass began to change in size over a 2-mo time period. Over time, the patient felt mild local pain and right cheek discomfort. His medical history included a hepatitis B virus infection for 20 years and 30 years of smoking. Gross examination of the excised specimen showed a gray-red and gray-white appearance and a soft texture lobulated external surface neoplasm that measured 9 cm × 8 cm × 7 cm and was well circumscribed by relative normal parotid gland tissue. In cross section, the cut surfaces of the neoplasm were multicystic and had a homogeneous scaly appearance. A small fluid was discovered in the cyst. Bilateral oxyphilic, cuboidal or polygonal epithelium cells and lymphoid intraparenchymal components were observed. Many medium- to large-sized lymphoid cells were observed diffusely in part of the neoplasm, and a few secondary lymphoid follicles were observed at the center or edge of the neoplasm. Immunohistochemical staining showed that the columnar oncocytic cells were positive for AE1/AE3; neoplastic cells located in coarctate follicular were positive for CD20, Pax-5, bcl-2 and bcl-6; and the adjacent diffusely medium- to large-sized lymphoid cells were positive for Pax-5, bcl-6, CD20, MUM-1, bcl-2 and CD79a. The bcl-6 (3q27) break-apart rearrangement was observed, and an Epstein Barr virus test was negative in the tumor cells. The patient survived 6 months after being diagnosed without any treatment.

CONCLUSION

WT-associated lymphoma is a very rare neoplasm in the parotid gland. Most cases are B cell non-Hodgkin lymphomas and involve middle-age and older males. This case highlights the extremely rare association of DLBCL arising from FL with WT and the importance of deliberate evaluation of the WT intraparenchymal stroma. Molecular detection techniques have potential advantages in the diagnosis of lymphoma with WT.

Warthin-like mucoepidermoid carcinoma of the parotid gland: a diagnostic and therapeutic dilemma

Mucoepidermoid carcinoma (MEC) is the most common malignant salivary gland tumor. Although the parotid gland is the most common site of involvement, other major salivary glands and the minor salivary glands—most commonly of the palate—also can be involved. The management of mucoepidermoid carcinoma depends on the grade of the tumor and the adequacy of resection. We present the case of a 56-year-old female presenting a painless progressive cheek mass over 2 months. Imaging and fine-needle aspiration cytology provided the diagnosis of Mucoepidermoid carcinoma. A superficial parotidectomy was done, and the histopathology revealed a predominantly cystic tumor with a bilayered epithelium of oncocytic and basal cells. Moderate nuclear pleomorphism with infiltration of atypical squamous cells in few glandular cysts was seen. Special staining revealed the presence of intracellular mucin. A diagnosis of Warthin-like variant of MEC was made, based on these findings. After the surgical procedures, the patient is disease-free at 8 months of follow-up. The Warthin-like variant is a rare variant of MEC with fewer than 10 cases described in the English literature. Various differential diagnoses include the malignant transformation of Wartin tumor (WT), squamous metaplasia of WT, and metastasis from a distant primary. We emphasize the role of routine microscopy in identifying rare variants of common malignancies. Even though translocation studies are helpful in diagnosis, the typical histopathological findings should confirm it.

Incidence of Non-Salivary Gland Neoplasms in Patients with Warthin Tumor: A Study of 73 Cases

Warthin tumor is the second most common benign parotid neoplasm. Its association with non-salivary gland neoplasms has been sporadically reported. We reviewed clinical records of Warthin tumor diagnosed on aspiration cytology and surgical pathology to determine if there is any association with other extra-salivary gland malignant neoplasms. Computer search was made for all cases of Warthin tumor diagnosed in the parotid gland by aspiration cytology and surgical pathology at our institution between January 2007 and August 2016. Clinical records of all cases were reviewed for any associated malignant neoplasms and any surgical follow up. All available cytology and histologic material was reviewed. Seventy-three patients (mean 66.9, M:F 1.1:1, age range 43 to 87 years) with Warthin tumor were identified. 45 (62%) were diagnosed on aspiration cytology only, 19 (26%) had cytologic diagnosis as well as concordant surgical follow up, and 9 (12%) were diagnosed based on surgical pathology only. Average age for patients with and without secondary malignancy was 70.5-years, and 63.4-years, respectively (p < 0.05). Average pack years for patients with and without secondary malignancy was 45.4, and 39.8, respectively (p > 0.05). Twenty-seven (37.0%) patients harbored a malignant neoplasm. Association of extra salivary gland malignant neoplasms in 37.0% of our cases suggest that the prevalence of secondary non-salivary neoplasms in patients harboring Warthin tumor might have been underestimated. Squamous cell carcinoma was the most commonly associated non-salivary malignant neoplasm. The association of Warthin tumor with smoking plays an important role in this increased rate of malignancy, and this is supported by the fact that smoking is highly associated with head and neck and lung cancers.

Follicular Lymphoma Diagnosed in Warthin Tumor: A Case Report and Review of the Literature

Warthin tumor is one of the most common benign salivary gland tumors. It is unusual and difficult to diagnose follicular lymphoma within the lymphoid tissue of Warthin tumor. We present a rare case of a 69-year-old man with systemic follicular lymphoma initially diagnosed in a Warthin tumor. Lymphomas occurring within Warthin tumors are rare, however, follicular lymphoma is most commonly reported. Because these patients require further treatment depending on the stage of a disease, it is important for a pathologist to review the histology of Warthin tumors diligently to identify occult lymphomas.

Infarcted Warthin tumor with mucoepidermoid carcinoma-like metaplasia: a case report and review of the literature

Background

Warthin tumor is a common, benign, painless salivary gland neoplasm. Rarely, Warthin tumors show large areas of squamous metaplasia; such Warthin tumors are called metaplastic or infarcted Warthin tumors because they are occasionally accompanied with tumor necrosis. The histological distinction between mucoepidermoid carcinomas and the metaplastic portions of Warthin tumors can be challenging; without a genetic study, mucoepidermoid carcinomas can be misdiagnosed as metaplastic Warthin tumors. We report a case of infarcted Warthin tumor partly showing mucoepidermoid carcinoma-like epithelial metaplasia. Only two cases of infarcted Warthin tumor similar to our case have been reported.

Case presentation

A 69-year-old Japanese man presented with a right parotid tumor. He had noticed the swelling on his right buccal region 1 year previously; the lesion had rapidly enlarged, with associated pain, 1 month previously. A radiological examination revealed a mass in the tail of the right parotid gland. Superficial parotidectomy was performed. On histological examination, the mass showed typical focal features of Warthin tumor; other areas showed coagulation necrosis of the tumor. These areas were surrounded by non-oncocytic epithelium comprising squamous and mucinous epithelial cells. Although cellular atypia of the non-oncocytic epithelium was not observed, a mixture of squamous and mucinous cells and lack of abundant lymphoid tissue mimicked low-grade mucoepidermoid carcinoma. Based on the results of fluorescence in situ hybridization, MAML2 gene rearrangement was not present in the typical portions of Warthin tumor and the mucoepidermoid carcinoma-like lesion. Therefore, a metaplastic or infarcted Warthin tumor was diagnosed. Our patient was disease-free 8 months after surgery.

Conclusions

Clinicians need to know that pain is a clinical symptom of infarcted/metaplastic Warthin tumor. Pathologists should be aware that a metaplastic Warthin tumor can mimic a low-grade mucoepidermoid carcinoma. Our case showed a mucoepidermoid carcinoma-like lesion that was confined near the area of tumor necrosis, and neither cytological atypia nor apparent invasive growth was present. These findings appeared to be histological clues of a metaplastic Warthin tumor rather than a mucoepidermoid carcinoma. Careful clinicopathological evaluation as well as genetic studies are needed to clarify the distinction between mucoepidermoid carcinoma and metaplastic portions of Warthin tumors.

Increased incidence of Warthin tumours of the parotid gland: a 42-year evaluation

AIM

To evaluate the frequency of Warthin tumours among parotid neoplasms over the past 42 years in a population in rural Germany and to identify potential risk factors.

METHODS

We conducted a retrospective case note evaluation from all patients who underwent parotid surgery between 1975 and 2017. The 42-year time period was evenly split into four quartiles.

RESULTS

A Warthin tumour was diagnosed in 265 out of 806 patients (32.9%). The frequency of Warthin tumour increased steadily from 20.6% in the first decade between 1975 and 1986 to 44.9% in the fourth decade between 2008 and 2017. The age of the patients decreased from 68 years in the first to 62 years in the fourth decade. The male-to-female ratio in Warthin tumour was reduced from 1:5.3 in the first to 1:2.1 in the fourth decade.

CONCLUSION

A Warthin tumour was the most common histological tumour type in the period from 1997 to 2017. We also found a high incidence of multiple tumours, a growing incidence in women and a decreasing age of patients. We propose a re-evaluation of the existing view of the epidemiology of benign parotid tumours, which proposes that pleomorphic adenoma is the most common benign parotid tumour.

Investigation of the surgical strategies for unilateral multifocal cystadenolymphomas of the parotid gland

OBJECTIVES

The aim of the study was to compare multifocal extracapsular dissection with complete parotidectomy in the treatment of unilateral multifocal cystadenolymphomas of the parotid gland.

MATERIALS AND METHODS

The records from all patients treated for unilateral multifocal cystadenolymphomas of the parotid gland at a tertiary referral center between 2000 and 2016 were retrospectively analyzed.

RESULTS

203 patients were included in the study. 96 patients were managed by multifocal extracapsular dissection, 107 patients underwent complete parotidectomy. Metachronous tumors were detected in 7 cases (3.4%) with a significant difference in the occurrence rate between multifocal extracapsular dissection (7/96, 7.3%) and complete parotidectomy (0/107, 0%) (p = 0.004). Permanent facial palsy was significantly more common after complete parotidectomy (21/107, 19.6%) than multifocal extracapsular dissection (2/96, 2.1%) (p = 0.000).

CONCLUSIONS

The functional benefit of multifocal extracapsular dissection was counterbalanced by the advantage of complete parotidectomy, in terms of recurrences. Extracapsular dissection is at its limit in cases of multifocal cystadenolymphomas and the indication for it should be thoroughly verified in each and every case.

Warthin's tumour in oral and maxillofacial regions: an 18-year retrospective study of 1084 cases in an eastern-Chinese population

There is little information in the English-language literature regarding Warthin's tumour (WT) in the eastern-Chinese population. A large retrospective study (1084 primary tumours over a period of 18years) was carried out to investigate the clinicopathological features (patients' gender, age and tumour location) of these tumours in this population. A total of 994 (91.7%) patients were male and 90 (8.3%) were female, with a male/female ratio of 11:1. The mean age was 56.48years (range 20-89years), with a peak incidence in the fifth to seventh decade (82.1%). The favorite primary site of the tumour was the parotid gland (n=1055), followed by intra-/peri-parotid lymph nodes (n=13), upper neck (n=10), submandibular gland (n=4) and upper lip (n=1). Multifocal WTs arose in 9.5% (103 patients) of cases whereas bilateral multifocal WTs were found in 0.65% (seven patients). In 24 (2.2%) patients, WT were found to coexist with other different types of neoplasm synchronously. The most common subtype of metaplasia was the squamous metaplasia (166/250, 66.4%). The usual treatment measure is (bilateral) superficial parotidectomy and the patients should be followed long term, in view of possible metachronous WT, even after prolonged time intervals.

Warthins tumor: Cyto histological spectrum with emphasis on diagnostic difficulties

Warthins tumour is characterized by the presence of epithelial proliferation in a lymphoid stroma. It has been categorized as Sieferts types: 1-4, depending on the proportions of the 2 components. Although FNA is fairly accurate in establishing the diagnosis, the cytologic diagnosis of this tumor has potential sources of error. This retrospective study was conducted in the Department of Pathology and Lab Medicine, of a tertiary care hospital. Cytology and surgical pathology records of past 15 years were screened. A total of 1200 FNAC cases of salivary gland lesions in the past 15 years were retrieved. 36 cases with presumptive cytodiagnosis of WT were identified and histopathological correlation was done. Histopathological correlation could be done in 24 cases. 19 out of 24 cases, were confirmed as WT. The 5 cases with discordance were analyzed for potential diagnostic pitfalls. The most common discordance was in the category of papillary proliferation with minimal lymphoid infiltrate. One case proved as oncocytoma and the other was papillary oncocyticcystadenoma. The other major pitfalls, were the interpretation of atypical squamoid cells. Their presence in a lymphoid background needs consideration of cytologic diagnosis of WT, mucoepidermoid carcinoma and metastatic squamous carcinoma. FNA showed an accuracy of 79% for WT. Cytological misinterpretation can thus occur in presence of morphology other than classical Siefert type1. An awareness of these potential pitfalls should push the need for avoiding single cytologic interpretation.

Mucous Cell Prosoplasia in Oral Pathologies: A Brief Review

One of the enigmas in cell differentiation process is prosoplasia, which is contemplated as forward differentiation. A well-known example of prosoplastic switch is mucous cell prosoplasia, which is the transformation of a simple squamous epithelial cell into mucous secreting cell. Numerous theories have been proposed for histogenesis of this phenomenon, which are comprehensively discussed in the present paper. Oral pathologies like odontogenic cysts and salivary gland tumours show mucous prosoplasia quite often; sometimes leading to diagnostic difficulties. In the present paper, efforts have been made to comprehensively discuss diverse aspects of mucous prosoplasia like histogenesis, theories and diagnostic importance in various oral pathologies.

Intraoral Salivary Duct Cyst: Clinical and Histopathologic Features of 177 Cases

The salivary duct cyst (SDC) is a reactive ductal ectasia most frequently seen in major salivary glands, and likely caused by obstruction. The aim of this study is to define the clinical and histopathologic spectrum of intraoral SDCs. Cases were retrieved from the archives of Harvard School of Dental Medicine/StrataDx, Inc. from January 2012 to August 2014. There were 177 cases of which 103 (58.2%) occurred in females, with a median age of 56 (range 2-95). Approximately half of cases (45.8%) presented in the area of the buccal mucosa, lower lip mucosa, or mandibular vestibule, and 23.2% presented in the floor of mouth. SDCs were lined at least focally by 1-2 layers of cuboidal/columnar epithelium in 85.3% of cases and showed varying degrees of metaplasia (oncocytic, mucous cell, squamous, ciliated, apocrine-like) in 68.4% of cases. Intraluminal mucous stasis was present in 41.8% of SDCs, incipient calcification was present within 4.5% of SDCs, and chronic obstructive sialadenitis was seen in 90.2% of cases. No cysts showed adenomatous ductal proliferations or true papillary structures with fibrovascular cores, although 41.2% exhibited reactive undulation of cyst lining. Thirty-nine 'papillary oncocytic cystadenoma-like' SDCs (22.0%) demonstrated complete oncocytic metaplasia and marked undulation. An additional seven such cysts (4.0%) had a 'Warthin tumor-like' lymphoplasmacytic infiltrate. Intraoral SDCs occur most commonly in the sixth decade of life in locations distinct from extravasation mucoceles, likely secondary to intraluminal obstruction. SDCs show diverse histopathology and certain phenotypic variants may be mistaken for papillary oncocytic cystadenoma or Warthin tumor.

Inflammation following invasive procedures for Warthin's tumour: A retrospective case series

OBJECTIVE

To determine the risk of inflammation associated with fine-needle aspiration during evaluation of Warthin's tumour.

DESIGN

Retrospective case series.

SETTING

Tertiary medical centre.

PARTICIPANTS

All patients who underwent fine-needle aspiration followed by parotidectomy between 1992 and 2009 for the diagnosis/evaluation of a parotid gland tumour.

MAIN OUTCOME MEASURE

Rate of fine-needle-aspiration-related parotitis in patients with Warthin's tumour or other parotid pathologies.

RESULTS

A total of 593 parotidectomies were performed in 553 patients during the study period, 96 (16.2%) for Warthin's tumour (study group) and 497 for other parotid-related pathologies (control group). Parotid gland inflammation following fine-needle aspiration was observed in 16 cases in the study group (16.7%) and eight (1.6%) in the control group (P<.001). On multivariate regression analysis, parotitis following fine-needle aspiration was more common in patients with Warthin's tumour than other parotid-related pathologies even after adjustment for possible confounders (P<.007). Signs of inflammation were noted during surgery in six cases in the study group (6.3%) and none in the control group (P<.001); respective rates of postoperative inflammation (wound infection) were 1.04% and 3.3% (P=NS). Management of parotitis consisted of hospitalisation and systemic antibiotic therapy.

CONCLUSIONS

Warthin's tumour is associated with a tenfold higher risk of inflammation compared to other parotid tumours following invasive procedures. Clinicians should be alert to this complication in order to initiate proper treatment and patients must be properly counselled.

Nodular Lymphocyte-Predominant Hodgkin Lymphoma in a Warthin Tumor of the Parotid Gland: A Case Report and Literature Review

Hodgkin lymphoma (HL) associated with Warthin tumor (WT) is extremely rare, accounting for only 3 cases of classical HLs. Here, we report for the first time the occurrence of a nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) involving the lymphoid stroma of a WT of the parotid gland. Pathogenesis of WT is controversial, with both a nodal and a parenchymal possible origin. On the other hand, extranodal involvement by HLs is uncommon. In our case, the coexistence of a WT and of a NLPHL within its stroma and in cervical lymph node emphasizes the importance of a careful evaluation of the lymphoid tissue in WT in order to exclude the possibility of an associated lymphoid malignancy.

An unusual initial presentation of mantle cell lymphoma arising from the lymphoid stroma of warthin tumor

Background

Warthin tumors presenting concomitantly with a lymphoma is vanishingly rare with only 15 reported cases in English literature. Herein, we report an unusual initial presentation of a mantle cell lymphoma involving the lymphoid stroma of a Warthin tumor.

Case presentation

A seventy-seven year old otherwise healthy gentleman with a 50-pack year smoking history presents with a slowly enlarging left cheek mass. CT scan of the neck demonstrated a left parotid gland tumor measuring 3.4 cm in greatest dimension. He underwent a left superficial parotidectomy, with subsequent histopathologic examination revealing a Warthin tumor with extensive expansion of the lymphoid stroma. Flow cytometric, immunohistochemical, and cytogenetic studies of the stromal component of the tumor confirmed the presence of a mantle cell lymphoma. Clinical staging demonstrated stage IVa disease, and was considered to be at low to intermediate risk due to the slow growth of the parotid lesion. The patient is undergoing close follow up with repeat PET-CT scans at six months.

Conclusion

To the best of our knowledge, this is the first well documented collision tumor between mantle cell lymphoma and a Warthin tumor. This case also brings to light the significance of thorough evaluation of the lymphoid component of Warthin tumor.

Intraparotid classical and nodular lymphocyte-predominant Hodgkin lymphoma: pattern analysis with emphasis on associated lymphadenoma-like proliferations

Most of the lymphoproliferative diseases involving the salivary glands represent indolent non-Hodgkin B-cell lymphoma (marginal zone lymphoma) related to chronic autoimmune sialadenitis (Sjögren disease). Other types of non-Hodgkin lymphomas involve the salivary glands less frequently. On rare occasions, classical Hodgkin lymphoma (CHL) and nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) present initially as a primary salivary gland mass. We analyzed a series of CHL (n=3) and NLPHL (n=6) presenting initially as parotid gland tumors concerning their pattern (parenchymal vs. intraparotid lymph node) and the presence of salivary inclusions and epithelial proliferations within the lymphoma infiltrate. The pattern of infiltration was determined on hematoxylin and eosin-stained slides assisted by immunostaining for pancytokeratin to highlight lobular salivary gland parenchyma. Patients included 6 male and 3 female individuals with a mean age of 62 years (range, 36 to 88 y). Lymphoma was localized within intraparotid lymph nodes in 8 cases and was limited to salivary parenchyma in 1 case. Parenchymal involvement in nodal-based cases was scored as absent (3) or minimal (5). Salivary inclusions (acini and ductules) within affected lymph nodes were noted in 6 cases (4/5 NLPHLs and 2/3 CHLs). In 3/6 NLPHL cases, salivary inclusions showed variable proliferative changes ranging from prominent lymphoepithelial lesions to cystic and oncocytic (Warthin-like) epithelial changes. Scanty small lymphoepithelial lesions were seen in 1 of the 3 CHL cases. One NLPHL in the intraparotid lymph node was accompanied by prominent lymphoepithelial sialadenitis in the absence of clinical signs of Sjögren disease. This study highlights that a majority of parotid gland Hodgkin lymphomas arise within intraparotid lymph nodes. Frequent entrapment and proliferation of salivary ducts and acini within the lymphoma infiltrate might mimic a variety of benign lymphoepithelial mass-forming lesions (nonsebaceous lymphadenoma, Warthin tumor, and autoimmune sialadenitis). Pancytokeratin stain is helpful for reliable assessment of the background architecture.

Squamous carcinoma arising in a parotid Warthin's tumour

Warthin's tumour is the second most common benign neoplasm to affect the salivary glands. It virtually affects the sole parotid gland. A sudden increase in a tumour's size is usually due to a malignant transformation of the tumour. The transformation of the lymphoid stroma into malignant lymphoma is relatively common, while an epithelial malignancy is extremely rare. In this paper, the authors present a case of squamous cell carcinoma arising in Warthin's tumour. The patient underwent enucleoresection of the tumour. Intraoperative frozen section revealed the presence of a cystic component associated with the squamous cell carcinoma areas. In consideration of the result of the intraoperative consultation, the surgeons decided to enlarge the previous resection by removal of a 30×25 mm cuff from the surrounding parotid tissue. Close follow-up was carried out and 12 months after surgery there was no evidence of recurrence or metastatic neoplasm.

Warthin's tumour: Aetiopathogenesis dilemma, ten years of our experience

Despite the volume of studies written after the initial report by Hildebrand (1895) on Warthin's tumour (WT), its aetiopathogenesis continues to be an unresolved and controversial question. Many different genetic and/or environmental aetiological factors seem to act on heterotopic ductal inclusions and may give rise to WT following an unknown tumorigenic event. Recent studies discussed the importance of immunological reactions during the formation of the tumour. A hypersensitive/allergic reaction may play a role in epithelial proliferation and may stimulate the reactivity of the germinal centres in the lymphoid stroma as showed at histological examination. The aim of this study was to inform readers of the current understanding of possible risk factors with a suggested aetiological role in Warthin's tumorigenesis. From 2001 to 2011, a total of 342 patients with benign salivary neoplasm were admitted in the Department of Maxillofacial Surgery of the University of Naples "Federico II". A histological diagnosis of WT was made in 115 of the patients (33.6%); these were retrospectively investigated in our study. Correlation between the onset of WT and positivity for autoimmune diseases and smoking habits was calculated. The incidence rate of autoimmune thyroiditis in our series (9.5%) was significantly greater than that of the general population (0.58%) (p < 0.001). Analysis of our series and review of the literature support the hypothesis that this tumour is the result of an autoimmune reaction. Further studies and larger series are required to confirm this hypothesis and investigate the role of other aetiological factors in WT genesis.

Synchronic nasopharyngeal and intraparotid warthin tumors: A case report and literature review

Warthin tumor is the second most frequent benign salivary gland tumor after pleomorphic adenoma; it occurs almost exclusively in the parotid gland and peri-parotideal lymph nodes, although it may rarely present in other locations. It may be multicentric and bilateral in a small percentage of cases. Nasopharyngeal Warthin tumor is very rare, and the presence of a synchronic WT involving nasopharynx and parotid is an exceptional event, as it has been described only twice in the literature. In this article we report an additional case of a synchronic Warthin tumor and review the related literature. Key words:Warthin tumor, synchronic WT, multicéntrico, nasopharynx.

Warthin's Tumour: A Case Report and Review on Pathogenesis and its Histological Subtypes

Warthin's tumour/ Papillary cystadenoma lymphomatosum (PCL) constitutes a minority of salivary gland neoplasms and it is a monomorphic adenoma which primarily involves the parotid gland. Warthin's tumour shows multiple cysts that have numerous papillations covered by bilayered columnar and basaloid oncocytic epithelium. The connective tissue portion shows proliferation of follicle- containing lymphoid tissue which necessitates careful distinction for diagnosis. Although, Warthin's tumour presents as a clinically benign, slow-growing, usually asymptomatic lesion with low rates of recurrences and malignant transformation, but still this tumour is considered unique because of its histological appearance and unknown origin and pathogenesis. Here, we report a case of Warthin's tumour of five years duration in a 50-year-old male patient in the right parotid gland and also review and discuss various concepts concerning the development of this tumour along with a comprehensive literature on its clinic-pathologic features.

[Patterns of xanthogranulomatous reaction in salivary glands. Histomorphological spectrum and differential diagnosis]

Xanthogranulomatous inflammation is an uncommon subtype of chronic inflammatory processes that has been mainly reported in the kidneys, gallbladder and other less common sites. Due to the presence of tumefactive mixed inflammatory infiltrates with variable involvement of surrounding soft tissues, this benign condition is often mistaken for a malignancy on clinical examination. In the salivary glands xanthogranulomatous inflammation is rare and mainly represents reactive changes secondary to a preexisting lesion, in particular infarcted Warthin tumors as well as ruptured ductal cysts and other sialectatic ductal changes. A special type of xanthogranulomatous salivary gland disease is represented by the rare primary (idiopathic) xanthogranulomatous sialadenitis without identifiable predisposing parenchymal or ductal lesions. The histological differential diagnosis is mainly based on the dominant histological pattern and encompasses among others inflammatory pseudotumors of various etiologies (e.g. inflammatory myofibroblastic tumor, IgG4-related disease and sarcoidosis), neoplastic and paraneoplastic xanthogranulomatosis, malignant lymphoma and carcinoma with secondary xanthogranulomatous reactions. Thus, identification of the underlying lesion is necessary for correct classification and to avoid overlooking more serious neoplastic or autoimmune diseases.

Adenolymphoma: A probing entity: Case report and review

Warthin's tumor undoubtedly is the most frequent monomorphic adenoma of the major salivary glands. Clinically, it appears as a slow-growing tumor often fluctuant on palpation due to its cystic nature. The treatment of choice is complete excision with wide tumor-free margins. This article highlights a case of Warthin's tumor of the parotid gland in an elderly male patient along with a review of the literature on the aforementioned pathology.

Lymphocyte recruitment via high endothelial venules in lymphoid stroma of Warthin's tumour

AIMS

Warthin's tumour is composed of bilayered oncocytic epithelium and organised lymphoid stroma, which resembles mucosa-associated lymphoid tissue (MALT); however, the histogenesis of the lymphoid stroma is not fully understood. We hypothesised that lymphocytes consisting of the stroma are recruited via high endothelial venules (HEVs) by the mechanism operating in normal lymphocyte homing in secondary lymphoid organs. The aim of this study was to determine immunohistochemically the molecules expressed on these HEVs.

METHODS

Tissue sections of Warthin's tumour (n = 10) were immunostained for vascular addressin-related antigens including peripheral lymph node addressin (PNAd) and mucosal addressin cell adhesion molecule 1 (MAdCAM-1). An L-selectin·IgM chimera in situ binding assay was also carried out. Triple immunostaining for PNAd, CD3, and CD20/CD79α was performed to determine which lymphocyte subsets are closely associated with these HEVs.

RESULTS

HEVs in the lymphoid stroma of Warthin's tumour express PNAd, which is detected by MECA-79 as well as recently developed monoclonal antibodies S1 and S2. These HEVs were bound by L-selectin·IgM chimeras in a calcium-dependent manner, and numbers of lymphocytes, particularly T cells, attached to these HEVs.

CONCLUSIONS

The lymphoid stroma of Warthin's tumour is most likely developed by lymphocytes recruited via HEVs.

Mycobacterial tuberculosis superimposed on a Warthin tumor

The concomitant occurrence of tuberculosis infection within a Warthin tumor is extremely rare, as only 6 cases have been previously reported in the English-language literature. We report a new case in a 92-year-old man, who presented with a 20-year history of a painless swelling in the right infra-auricular area that had recently become painful and larger. The patient had no history of tuberculosis, weight loss, or chronic cough. The fluctuant mass was aspirated, but histopathology and routine culture were negative. Computed tomography identified a 5-cm, heterogeneous, enhancing mass with multiple, variably sized, low-density areas without surrounding edema in the area of the right parotid gland. Complete excision was performed to relieve the patient's symptoms. Histopathology diagnosed an acid-fast bacillus infection within a Warthin tumor. On polymerase chain reaction testing, formalin-fixed, paraffin-embedded tissue was negative for tuberculosis, but subsequent culture identified Mycobacterium tuberculosis. Initially, the patient refused antituberculosis therapy, but he relented when miliary pulmonary tuberculosis was diagnosed 11 weeks postoperatively.

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.

Rare Malignant and Benign Salivary Gland Epithelial Tumors

Although at least 24 distinct histologic salivary gland carcinomas exist, many of them are rare, comprising only 1% to 2% of all salivary gland tumors. These include epithelial-myoepithelial carcinoma, (hyalinizing) clear cell carcinoma, basal cell adenocarcinoma, cystadenocarcinoma, low-grade salivary duct carcinoma (low-grade cribriform cystadenocarcinoma), oncocytic carcinoma, and adenocarcinoma not otherwise specified. Few tumors (clear cell carcinoma and basal cell adenocarcinoma) have unique molecular correlates. Benign tumors, although histologically less diverse, are far more common, with pleomorphic adenoma and Warthin tumor the most common salivary gland tumors. Many benign tumors have malignant counterparts for which histologic distinction can pose diagnostic challenge.