Lymphoepithelial Carcinoma of Salivary Gland EBV-association in Endemic versus Non-Endemic Patients: A Report of 16 Cases

Lymphoepithelial carcinoma of the parotid gland

Primary lymphoepithelial carcinoma of the salivary glands is an exceptional oncological condition that predominantly emerges within the parotid gland. A significant prevalence of lymphoepithelial carcinoma has been reported in the Inuit population, along with an associated positive serology for Epstein-Barr virus in these endemic regions. In this paper, we present a case of primary lymphoepithelial carcinoma of the parotid gland in a 68-year-old female patient with a history of diabetes and hypertension residing in a non-endemic area. Histology plays a critical role in the definitive diagnosis, and confirming the primary origin of lymphoepithelial carcinoma after ruling out metastasis from undifferentiated nasopharyngeal carcinoma. The mainstay of treatment is a combination of surgical resection and adjuvant radiotherapy. Inoperable forms are typically managed with chemoradiotherapy.

The differential diagnosis of lymphoepithelial lesion of the salivary gland

The differential diagnosis of salivary gland lesions with epithelial components and lymphoid stroma is often challenging. Salivary gland carcinoma with tumor-associated lymphoid proliferation, tumors composed of both epithelial and lymphoid components, lymphoid neoplasms in the salivary gland, and inflammatory lesions are all included in this category. It encompasses inflammatory lesions and neoplastic lesions. With the exception of Warthin tumors, these lesions are rare, making them more difficult to diagnose. Carcinoma showing thymus-like elements has recently been reported in the salivary gland. Similar to thymic carcinoma, tumor cells are positive for CD5 and are accompanied by T lymphocytes.

First Case Report of Bilateral Parotid Lymphoepithelial Carcinoma

Background/Aim

The parotid is the largest salivary gland and is located anteriorly to the sternocleidomastoid muscle and laterally to the ramus of the mandible. Neoplasms in this gland are relatively rare, with 80% being benign and 20% malignant, primarily represented by mucoepidermoid carcinoma. In the head and neck region, lymphoepithelial carcinoma (LEC) accounts for 0.4% of malignant salivary gland tumors.

Case Report

A 35-year-old man with no previous comorbidities was admitted to a Head and Neck Surgery Specialty Service for a painless right cervical mass of uncertain growth. Extensive diagnostic investigation revealed involvement of the contralateral parotid, associated with systemic lymph node enlargement. Thus, adjuvant radiotherapy was decided by the treating team.

Conclusion

This case confirms the heterogeneous features and distinctive behavior that the disease can present, as seen with bilateral parotid LEC.

Carcinoma showing thymus-like elements (CASTLE) with amyloid deposition in the parotid gland

Carcinoma showing thymus-like elements (CASTLE) is a rare tumor that commonly occurs in the thyroid gland. Extrathyroidal CASTLE is rarer, and only 11 cases of CASTLE of major salivary glands have been reported to date. We report the first case of amyloid deposition in parotid CASTLE. A 63-year-old man presented with a slowly growing mass in the left parotid region. Computed tomography revealed an approximately 28 × 23 mm mass lesion in the left parotid gland, and squamous cell carcinoma was suspected on biopsy. The patient underwent a parotidectomy with neck dissection. Morphologically, the tumor cells were squamoid and formed nests with lymphoid infiltration. Immunohistochemically, the tumor cells exhibited immunoreactivity for CD5, CD117/c-kit and Bcl-2, p40, and CK5 but not for p16. We diagnosed the tumor as parotid CASTLE. Amyloid deposition was also observed in the primary tumor and metastatic lymph node lesions, which were immunoreactive for cytokeratin 5. Tumor cytokeratin-derived amyloid deposition may be one of characteristics of parotid CASTLE.

Challenging Tumor Heterogeneity with HER2, p16 and Somatostatin Receptor 2 Expression in a Case of EBV-Associated Lymphoepithelial Carcinoma of the Salivary Gland

BACKGROUND

Lymphoepithelial carcinoma of the salivary glands (LECSG) is a rare disease in the Western hemisphere that is typically associated with an EBV infection. The molecular mechanisms of LECSG tumorigenesis are poorly understood.

RESULTS

Here we report a case of EBV-associated LECSG with an unusual immunophenotype. The tumor exhibited bi-morphic histological features with a mutually exclusive expression of HER2 and p16. The p16-positive domain of the tumor immunohistochemically co-expressed late membrane protein 1 (LMP-1), while the HER2 positive domain did not. Both tumor regions expressed SSTR2.

METHODS

In situ hybridization confirmed the EBV origin of the tumor while extensive immunohistochemical characterization and the recently established RNA-based next generation sequencing panel ("SalvGlandDx" panel) did not reveal evidence for another salivary gland neoplasm. No HPV co-infection was detected by in situ hybridization or PCR-based screenings and no ERBB2 gene amplification was detected by fluorescence in situ hybridization.

CONCLUSION

These findings suggest tumor heterogeneity and lack of genomic aberrations in EBV-associated LECSGs. The heterogenous and unusual immunohistochemical features explain the diagnostic difficulties and simultaneously extend the immunophenotype spectrum of this tumor entity.

Intraoral salivary lymphoepithelial carcinoma: clinicopathologic and immunophenotypic characterization of 3 cases indicates elevated programmed death-ligand 1 expression

OBJECTIVE

Intraoral salivary lymphoepithelial carcinoma (ISLEC) is a rare malignancy with programmed death-ligand 1 (PD-L1) expression levels that have been greatly understudied. We examined the clinicopathologic and immunophenotypic characteristics, including PD-L1 levels, of 3 cases of ISLEC.

STUDY DESIGN

We searched the archives of 2 oral and maxillofacial pathology laboratories for specimens diagnosed as ISLEC between 1985 and 2022. We collected patient demographic and clinical data. Immunostaining for AE1/AE3, CK7, CD3, CD20, p16, p53, Ki67, and PD-L1 (SP263), as well as Epstein-Barr virus-encoded small RNAs (EBER) in situ hybridization (ISH) were performed.

RESULTS

All 3 cases affected males aged 42 to 84 years (median = 61y) and involved the floor of the mouth, soft palate/uvula, and tongue. The lesions showed diffuse infiltration by non-keratinizing sheets and islands of undifferentiated carcinoma cells with associated dense lymphoplasmacytic inflammation. Immunohistochemically, all tumors showed AE1/AE3 positivity, selective p53 staining, and negativity for CK7 and p16. Ki67 highlighted 20%-80% of lesional cells. The inflammatory infiltrate comprised a mixed population of T and B lymphocytes. EBER ISH was positive in one case. All ISLECs displayed membranous, focal-to-diffuse, PD-L1 staining with tumor proportion score > 95% in two and 40-50% in the third case.

CONCLUSIONS

The clinicopathologic and immunophenotypic characteristics of the cases we examined highlight the rarity of ISLEC and indicate overall high PD-L1 levels in this type of malignancy, rendering patients with ISLEC potential candidates for targeted α-PD-1/PD-L1 immunotherapy.

Nonsebaceous Lymphadenoma of the Salivary Glands: A Potential Overdiagnosis Pitfall

Nonsebaceous lymphadenoma is a rare benign salivary tumor. It is easily misdiagnosed as lymphoepithelial carcinoma, leading to overtreatment. Some patients experience sequelae after undergoing cervical lymph node resection and adjuvant treatment, so it is critical to distinguish these entities. We describe the histopathological and immunohistochemical features of this rare entity in 3 cases and discuss the differential diagnosis and histogenesis. Nonsebaceous lymphadenoma can be distinguished from lymphoepithelial carcinoma by the following histological features: There is a lymph node-like form at low magnification, with prominent proliferating epithelial nests but no destructive growth pattern; variable numbers of tubuloglandular components are always seen in proliferating epithelial nests, which transition to cystically dilated salivary ducts; no lesion necrosis exists; and mitotic figures are absent or rare. No patients experienced recurrence during the 8- to 69-month (mean, 29 months) follow-up.

Primary Lymphoepithelial Carcinoma of the Submandibular Gland in A Young Patient: A Case Report

Lymphoepithelial carcinoma (LEC) is a rare entity of malignancy. It has been associated with Epstein-Barr virus (EBV), and in regions where it is endemic, such as Southeast Asia, EBV is typically associated with nasopharyngeal carcinoma. The incidence of such malignancies in the young population is unusual. Here we report a 17-year-old with a 5-year history of a painless right submandibular mass presenting with a sudden increase in size for one month before surgery. Neck examination revealed a firm right submandibular gland measuring five by five cm, with an irregular surface, non-tender with normal overlying skin. We performed a fine needle aspiration cytology (FNAC), and he underwent computed tomography (CT) scan of the neck. He underwent a right submandibulectomy. Lymph nodes from levels I and II were also removed. The final histopathology was reported as LEC. Following this tissue diagnosis, another follow-up surgery, a modified radical neck dissection, was carried out for locoregional clearance. Postoperatively, he completed chemoradiotherapy treatment and is now on regular follow-up.

Epstein‑Barr virus‑associated lymphoepithelial carcinoma arising in the parotid gland: A case report and literature review

A 60-year-old woman presented with a 3-year history of a slow-growing, painless mass in their left parotid gland. Ultrasonography revealed a well-circumscribed, lobulated, hypoechoic mass measuring 19x12x10 mm in the left parotid gland. Computed tomography revealed a well-circumscribed, solid mass with homogeneous enhancement. Fluorodeoxyglucose-positron emission tomography revealed uptake by the tumor but no uptake in other organs, including the nasopharynx. The patient underwent superficial parotidectomy with adequate safety margins and selective neck dissection followed by radiotherapy. No facial paralysis or recurrence of the tumor had been observed as of 20 months post-operation. Histologically, the tumor was composed of sheets of syncytial cancer cells with prominent nucleoli in a dense lymphoplasmacytic background. Epstein-Barr virus (EBV)-encoded RNA in situ hybridization was diffusely positive in the tumor cells. These findings indicated that the tumor was an EBV-associated lymphoepithelial carcinoma. Metastasis, especially from the nasopharynx, was excluded endoscopically and radiologically. Targeted next-generation sequencing of 160 cancer-related genes using the surgical specimen revealed no mutations, including known significant mutations detected in EBV-associated nasopharyngeal carcinoma.

Epstein-Barr Virus (EBV) Epithelial Associated Malignancies: Exploring Pathologies and Current Treatments

Epstein-Barr virus (EBV) is one of eight known herpesviruses with the potential to infect humans. Globally, it is estimated that between 90-95% of the population has been infected with EBV. EBV is an oncogenic virus that has been strongly linked to various epithelial malignancies such as nasopharyngeal and gastric cancer. Recent evidence suggests a link between EBV and breast cancer. Additionally, there are other, rarer cancers with weaker evidence linking them to EBV. In this review, we discuss the currently known epithelial malignancies associated with EBV. Additionally, we discuss and establish which treatments and therapies are most recommended for each cancer associated with EBV.

Lymphoepithelial Subtype of Oral Squamous Cell Carcinoma: Report of an EBV-Negative Case and Literature Review

Lymphoepithelial carcinoma (LEC) of the oral mucosa is a rare histopathologic subtype of squamous cell carcinoma (SCC), which shares morphologic similarities with nasopharyngeal carcinoma (NPC), non-keratinizing undifferentiated subtype. The admixture of neoplastic epithelial tumor cells and a dense lymphoplasmacytic infiltrate makes microscopic diagnosis challenging. LEC etiopathogenesis has been variably associated with Epstein–Barr virus (EBV) infection, depending on the specific anatomic location and racial predilection, with a higher incidence in endemic populations. Although described in several subsites of the head and neck region, including the major salivary glands, the oral mucosa is considered an infrequent location for LEC development, deriving either from minor salivary glands (MSGs) or the surface epithelium. Herein, we report a rare case of an EBV-negative LEC arising from the oral surface epithelium, presenting as gingival swelling, and review the pertinent English-language literature, which revealed only 26 previously reported oral LECs. Our case is only the fourth oral LEC originating from the surface epithelium and the first one to affect the gingiva.

Lymphoepithelial carcinoma of the parotid gland: Clinicopathological analysis of 146 cases from a single institute

BACKGROUND

Parotid lymphoepithelial carcinoma (LEC) is a rare malignant tumor. The purpose of this study was to investigate the clinicopathological features of parotid LEC.

METHODS

All patients clinicopathological information diagnosed parotid LEC from 2005 to 2017 were analyzed.

RESULTS

A total of 146 cases of parotid LECs were identified. Of these, 126 (86.3%) were primary and 20 (13.7%) were secondary LECs. Patients with secondary LEC tended to have tumors with earlier TNM staging than those with primary (p = 0.031). The tumor cells in 87 (94.6%, 87/92) cases tested positive for Epstein-Barr virus (EBV). Cervical node metastases were present at diagnosis in 46 (31.5%) cases. Overall survival at 5 and 10 years was 97.0% and 90.8%, respectively. Older age was an adverse prognostic indicator for overall survival (p < 0.001).

CONCLUSIONS

Parotid LEC is associated with EBV and an increased rate of cervical node metastases. However, most patients, especially younger ones, have a good prognosis.

Warthin-like mucoepidermoid carcinoma of the parotid gland: a clinicopathological analysis of two cases

Mucoepidermoid carcinoma (MEC) is the most common malignant tumour of the salivary gland, primarily involving the parotid gland. Here, the cases of two patients, aged 47 and 67 years, respectively, who underwent surgery for pathologically confirmed Warthin-like MEC of the parotid gland between January 2019 and December 2019 in Anyang Tumour Hospital, are described. In each case, the tumour consisted of epithelial and lymphoid cell components, covered with two or more layers of epithelium, with visible scattered mucous cells, and lymphoid stroma with a large number of lymphocytes and germinal centres formed. Most importantly, the tumours lacked the well-organized, bilayered oncocytic epithelial structure that is characteristic of Warthin’s tumour. Mastermind like transcriptional coactivator 2 (MAML2) gene rearrangements were identified in the tumour cells using break-apart fluorescence in situ hybridization (FISH) probes, confirming the diagnosis of Warthin-like MEC. Post-operatively, patients have remained disease free for 31 and 27 months, respectively. Warthin-like MEC of the parotid gland is rare and is often misdiagnosed as metaplastic Warthin’s tumour. Diagnosis depends mainly on the unique clinicopathologic features together with FISH analyses.

Clinical features in salivary gland lymphoepithelial carcinoma in 10 patients: Case series and literature review

Objective

Lymphoepithelial carcinoma (LEC) accounts for 0.4% of malignant tumors of the salivary gland and 0.8% of parotid gland malignancies. Over the past 50 years, less than 300 cases have been reported in the literature. The purpose of this study was to investigate the characteristics of salivary gland LEC.

Methods

We retrospectively reviewed the medical records and analyzed clinical data obtained from 10 patients seen at our hospital between 2005 and 2020 with salivary gland LEC.

Results

All patients presented with a self‐palpable, non‐tender, hard swelling, or lump near the jaw or infra‐auricular region. Most cases (n = 8) were of solitary tumors, and enhancing patterns on computed tomography mainly were homogenous (n = 8). Interestingly, eight patients tested positive for the Epstein–Barr encoding region in in situ hybridization. Still, only three patients had detectable circulating Epstein–Barr virus (EBV) DNA, and one patient had detectable EBV IgA. All patients underwent complete tumor resection, followed by radiotherapy, and six also underwent chemotherapy. Nine patients became disease‐free within 5 years, and one died due to disease 4 years after surgery.

Conclusion

Although rare and considered to be a high‐risk malignancy, LECs have favorable treatment outcomes. Circulating EBV DNA is still not considered a marker for preoperative assessment or postoperative treatment response. The role of EBV DNA requires further investigation.

Level of Evidence: 4

Practical immunohistochemistry in the classification of salivary gland neoplasms

Diagnosis of salivary gland neoplasms can be challenging for surgical pathologists due to low incidence of tumors as well as overlapping histologic features. On small biopsy, the most important information to be conveyed for clinical management is the distinction between a benign/low grade tumor and a high grade carcinoma. This review will discuss the differential diagnosis of salivary gland tumors based on four broad morphologic patterns: basaloid/tubular/cribriform, (micro)cystic/secretory/mucinous, solid-nested/clear-spindled, and oncocytic/oncocytoid. With the assistance of immunohistochemistry, demonstration of the number of cell types (mainly epithelial versus myoepithelial/basal) can further subclassify tumors within these morphologic categories. Additional tumor-specific immunomarkers are useful in some cases. Underlying tumor-specific genetic anomalies can be of value, however, immunohistochemical correlates are only available for some. When used judiciously, in the correct morphologic context, and with knowledge of their limitations, immunohistochemical stains can aid in differentiating tumors with similar morphology.

Undifferentiated and dedifferentiated head and neck carcinomas

Undifferentiated carcinomas arising at salivary gland and head and neck mucosal sites may originate either de novo or through a process of dedifferentiation of a differentiated carcinoma. While in the latter group the diagnosis is largely dependent on the identification of the differentiated component or recognition of a specific genotype, the classification of undifferentiated carcinomas that lack a differentiated component is mainly based on the identification of specific genetic drivers, like for example the NUTM1 fusions in NUT carcinoma. A further category is represented by virus associated carcinomas (mainly HPV and EBV), that frequently displays an undifferentiated morphology. Overall, these tumors often represent a diagnostic challenge, especially in small biopsies. This review summarizes and discuss the diagnostic approach to the main head and neck carcinoma types that frequently or occasionally display an undifferentiated appearance, with a focus on salivary gland, oropharyngeal, nasopharyngeal and sinonasal subsites.

Clinical analysis of 12 patients with primary lymphoepithelial carcinoma of the parotid gland

BACKGROUND AND PURPOSE

The WHO recently designated salivary gland lymphoepithelial carcinoma as a unique malignant tumor that most commonly occurs in the parotid gland. This is a rare cancer and there are few reports in the literature. Among 854 patients with parotid gland tumors who were admitted to our institution, we diagnosed 12 patients (1.41%) with parotid lymphoepithelial carcinoma.

METHODS

Retrospective analysis of 12 patients with parotid lymphoepithelial carcinoma diagnosed by the Department of Pathology, Xiangya Hospital of Central South University.

RESULTS

All 12 patients had unilateral parotid gland disease and 8 had cervical lymph node metastasis. Five patients received PCR testing for the Epstein-Barr virus and two were positive. All patients received surgical treatment, two received surgical resection alone, nine received surgery and postoperative radiotherapy and chemotherapy, and one received surgery and postoperative chemotherapy. The postoperative follow-up time ranged from 13 to 77 months. As of the last follow-up, eight patients were tumor-free, one patient was lost to follow-up, and three patients died. The main cause of death was local tumor recurrence and multiple metastases throughout the body.

CONCLUSION

Parotid lymphoepithelial carcinoma is a malignant neoplasm characterized by proliferation, invasion, and inclusion of poorly differentiated or undifferentiated carcinoma, and a high rate of metastasis to ipsilateral cervical lymph nodes. The comprehensive treatment method consists of radical resection combined with postoperative radiotherapy and chemotherapy. After this comprehensive treatment, the 1-year, 3-year, and 5-year overall survival rates of our patients were 100%, 78.8%, and 39.4%.

Lymphoepithelial Carcinoma of Salivary Glands

Lymphoepithelial carcinoma of salivary glands (LECSG) is an uncommon neoplasm. This article summarizes the findings of 438 cases in a review of the literature. Concurrent lymphoepithelial lesions may suggest a primary tumor. The tumor shows a nonkeratinizing carcinoma intimately associated with a rich lymphohistiocytic infiltrate, destroying adjacent salivary gland tissue. Irrespective of race or ethnicity, the tumors usually express Epstein-Barr virus, with Epstein-Barr virus encoded small RNA (EBER) and/or latent membrane protein-1 (LMP-1), although a subset does not. There is an overall good prognosis of about 80% at 5 years.