Analysis of lymphoepithelioma and lymphoepithelioma-like carcinomas for Epstein-Barr viral genomes by in situ hybridization

Non-Squamous Cell Carcinoma of the Larynx: A State-of-the-Art Review

(1) Background: Non-squamous cell laryngeal carcinoma includes endothelial tumors, such as minor salivary gland tumors, lymphoepithelial tumors, neuroendocrine tumors, soft and hard tissue sarcomas, and malignant melanomas. (2) Methods: A state-of-the-art review using the MEDLINE/PUBMED, Google Scholar, Ovid Medline, Embase, and Scopus electronic databases was performed. (3) Conclusions: In order to optimize overall treatment outcomes, a multidisciplinary, patient-centered approach to the management of non-SCC of the larynx must be adopted universally; a national or international registry on non-SCC laryngeal cancer can be useful to improve understanding about the behavior of this kind of tumor.

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.

Thymic Lymphoepithelial Carcinoma Associated with Epstein-Barr Virus: Experiences and Literature Review

Thymic lymphoepithelial carcinoma (TLEC) is a primary thymic carcinoma that accounts for about 14% of all thymic epithelial tumors and is classified into 14 types. The histological morphology is similar to lymphoepithelioma, a type of undifferentiated nasopharyngeal carcinoma. It has been reported that squamous carcinoma accounts for approximately 80% of thymic carcinoma, followed by TLEC, which accounts for 6%. TLEC has been reported to be associated with Epstein-Barr virus (EBV), with EBV infection in TLEC tumor cells first noted by Lyvraz et al. in 1985. Tumors shown to be EBV-positive are classified as TLEC if lymphoplasmacytic infiltration is lacking. However, only about 50% of the cases are positive for EBV, which is lower compared to nasopharyngeal lymphoepithelioma. Instances of EBV infection in other types of thymic epithelial tumor have been reported at lower rates, which suggests that EBV infection may have an important influence on the carcinogenesis of TLEC, though the etiology is unknown. TLEC is a highly malignant tumor with poor prognosis, as affected patients have a median survival time of 22 months, according to 58 cases from the literature, while the 5-year survival rate is 34.4%. Presently, prognosis is not considered to be affected by the presence or absence of EBV positivity.

Lymphoepithelial Carcinoma in the Lateral Tongue: The Case Report

Lymphoepithelial carcinoma (LEC) of the tongue is a rare subtype of squamous cell carcinoma. Histologically, it is an undifferentiated carcinoma with rich lymphocyte and plasma cell infiltration. The most common location for LEC in the head and neck is the salivary glands, and LEC of the oral cavity is extremely rare. The second case report of LEC in the lateral tongue is presented. In addition, a review of the literature was performed, and the relationship between LEC and Epstein–Barr virus infection was considered.

The evolution of the nasopharyngeal carcinoma staging system over a 10-year period: implications for future revisions

BACKGROUND

The classification criteria and staging groups for nasopharyngeal carcinoma described in the Union for International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) staging system have been revised over time. This study assessed the proportion of patients whose staging and treatment strategy have changed due to revisions of the UICC/AJCC staging system over the past 10 years (ie, from the sixth edition to the eighth edition), to provide information for further refinement.

METHODS

We retrospectively reviewed 1901 patients with non-metastatic nasopharyngeal carcinoma treated in our cancer center between November 2009 and June 2012. The Akaike information criterion and Harrell concordance index were applied to evaluate the performance of the staging system.

RESULTS

In total, 25 (1.3%) of the 1901 patients who were staged as T2a according to the sixth edition system were downgraded to T1 in the eighth edition; 430 (22.6%) staged as N0 in the sixth edition were upgraded to N1 in the eighth edition; 106 (5.6%) staged as N1/2 in the sixth edition were upgraded to N3 in the eighth edition. In addition, 51 (2.7%) and 25 (1.3%) of the study population were upstaged from stage I to stage II and stage II to stage IVa, respectively; 10 (0.5%) was downgraded from stage II to stage I. The survival curves of adjacent N categories and staging groups defined by eighth classification system were well-separated. However, there was no significant difference in the locoregional failure-free survival (P = 0.730) and disease-free survival (P = 0.690) rates between the T2 and T3 categories in the eighth edition classification system.

CONCLUSIONS

Modifications to the tumor-node-metastasis staging system over the past 10 years have resulted in N classification changes in numerous cases. Although the eighth edition tumor-node-metastasis staging system better predicts survival outcomes, the T classification could be simplified in future revisions.

The evolution of nasopharyngeal carcinoma staging

The prevalence of nasopharyngeal carcinoma is characterized by an unbalanced distribution: the disease is particularly prevalent in East and Southeast Asia. In this article, we review the evolution of the International Union Against Cancer/American Joint Committee on Cancer staging system for nasopharyngeal carcinoma. With the increasing using of newer imaging methods, more advanced radiotherapy techniques and systemic chemotherapy, we also discuss newer clinical features that might affect staging. Finally, we propose the future direction of staging and potential prognostic factors that have a major influence on the treatment outcomes of this disease.

Patterns of EBV-positive cervical lymph node involvement in head and neck cancer and implications for the management of nasopharyngeal carcinoma T0 classification

OBJECTIVES

Epstein-Barr virus (EBV)-positive cervical lymph node (CLN) metastasis of unknown primary origin is classified as nasopharyngeal carcinoma (NPC) T0 by the American Joint Committee on Cancer staging manual (8th edition). We aimed to investigate the possible primary sites and patterns of EBV-positive CLN metastases and to provide implications for the management of NPC T0 classification.

MATERIALS AND METHODS

We retrospectively reviewed 269 patients with newly diagnosed EBV-positive CLN metastatic disease who underwent EBV detection via EBV-encoded RNA in situ hybridization. Fifteen patients with unknown primary tumors underwent follow-up after initial treatment.

RESULTS

In patients with EBV-positive CLNs, the most common primary sites after the nasopharynx (51.7%) were the salivary gland (24.5%), lung (7.8%), oropharynx (3.3%), nasal cavity/maxillary (3.3%), oral cavity (2.2%), orbit (1.1%), and liver (0.4%). No primary site was found in 15 patients (5.6%). For salivary gland malignancies, level II and I were the most frequently involved regions. Tumors arising from the lung or liver metastasized to the lower neck (level IV, V, and VI) rather than the upper neck. After initial treatment, 2/15 patients with EBV-positive CLNs of unknown primary exhibited primary NPC and oropharyngeal tumor, respectively. Further, even without prophylactic irradiation to the nasopharynx, only one of 13 unknown primary patients developed NPC.

CONCLUSIONS

The origins of EBV-positive CLNs may not be restricted to the nasopharynx alone, and are likely to involve the head and neck or non-head and neck regions. NPC T0 classification should be cautiously assigned to such tumors.

Lymphoepithelioma-Like Carcinoma of the Uterine Cervix: A Pathologic Study of Eight Cases With Emphasis on the Association With Human Papillomavirus

Objectives

Lymphoepithelioma-like carcinoma (LELC) of the uterine cervix is a rare tumor. The goal of this study was to evaluate a series of cases of cervical LELC and to investigate possible association with human papillomavirus (HPV) and/or Epstein-Barr virus (EBV).

Methods

Immunohistochemistry for p63, p16, human leukocyte antigen-D related (HLA-DR), and B-cell lymphoma 2 (BCL-2); in situ hybridization (ISH) for EBV and HPV; and polymerase chain reaction (PCR) genotyping were performed. Mismatch repair (MMR) studies and PD-L1 status were obtained.

Results

We found eight cases of LELC. Tumors demonstrated sheets of cells containing vesicular nuclei, amphiphilic cytoplasm, and dense peri- and intratumoral lymphocytic infiltrates. All tumors stained for p63, p16, and HLA-DR; two also stained for BCL-2. When combining ISH and PCR results, seven tumors were HPV positive; they were all Epstein-Barr encoding region negative. All cases were MMR intact, and most overexpressed PD-L1.

Conclusions

This study shows that cervical LELCs are associated with HPV and not EBV.

Clinical Utility of In Situ Hybridization Assays in Head and Neck Neoplasms

Head and neck pathology present a unique set of challenges including the morphological diversity of the neoplasms and presentation of metastases of unknown primary origin. The detection of human papillomavirus and Epstein-Barr virus associated with squamous cell carcinoma and newer entities like HPV-related carcinoma with adenoid cystic like features have critical prognostic and management implications. In salivary gland neoplasms, differential diagnoses can be broad and include non-neoplastic conditions as well as benign and malignant neoplasms. The detection of specific gene rearrangements can be immensely helpful in reaching the diagnosis in pleomorphic adenoma, mucoepidermoid carcinoma, secretory carcinoma, hyalinizing clear cell carcinoma and adenoid cystic carcinoma. Furthermore, molecular techniques are essential in diagnosis of small round blue cell neoplasms and spindle cell neoplasms including Ewing sarcoma, rhabdomyosarcoma, synovial sarcoma, biphenotypic sinonasal sarcoma, dermatofibrosarcoma protuberans, nodular fasciitis and inflammatory myofibroblastic tumor. The detection of genetic rearrangements is also important in lymphomas particularly in identifying 'double-hit' and 'triple-hit' lymphomas in diffuse large B cell lymphoma. This article reviews the use of in situ hybridization in the diagnosis of these neoplasms.

Presence of lytic Epstein-Barr virus infection in nasopharyngeal carcinoma

BACKGROUND

Chromogenic Epstein-Barr virus-encoded RNA (EBER) in situ hybridization (EBER-ISH) is the gold standard to detect Epstein-Barr virus (EBV) but it is difficult to use in conjunction with immunohistochemistry (IHC). In this study, our purpose was to validate the sensitivity and specificity of RNAscope in detection of EBV infection in nasal epithelium and its stroma.

METHODS

Fluorescence-based RNAscope EBER-ISH, BRLF1-ISH, and lineage marker-IHC were performed on archived formalin-fixed paraffin-embedded tissues from normal nasal cavity (n = 5), nasopharynx (n = 8), and nasopharyngeal carcinoma (NPC) specimens (n = 10).

RESULTS

The EBERs were detected in 10 of 10 NPC samples but was absent in all normal tissues from the nasal cavity and nasopharynx. The EBERs were exclusively located in pan-cytokeratin (pan-CK)-positive tumor epithelial cells but not in CD45-positive leukocytes and vimentin-positive stromal fibroblasts. The level of EBER expression varied in tumor cells within patient and between patients as well. Additionally, 5 of 10 patients had positive BRLF-ISH.

CONCLUSION

We developed a simple and reproducible method to simultaneously detect mRNA and protein in formalin-fixed paraffin-embedded tissues of NPC. As a single staining, traditional EBER continues to be useful; however, for interpretation of the phenotype of EBV-infected cells, RNAscope is superior. Significantly, we showed that lytic EBV infection took place in NPC tumors.

Intrahepatic Cholangiocarcinoma With Lymphoepithelioma-like Carcinoma Components Not Associated With Epstein-Barr Virus: Report of a Case

A carcinoma displaying undifferentiated features with dense lymphoplasmacytic infiltration is defined as lymphoepithelioma-like carcinoma (LELC). Intrahepatic cholangiocarcinoma (ICC) with LELC components is rare, and most LELCs are associated with Epstein-Barr virus (EBV). We report here on a case of ICC with LELC components not associated with EBV. A 65-year-old woman was incidentally found to have a hepatic tumor in the caudate lobe. An extended right hepatectomy with lymphadenectomy was performed. Histologically, the tumor was mainly composed of large undifferentiated epithelial cells with vesicular nuclei, prominent nucleoli, indistinct cell borders, and heavy small lymphocytic infiltration, which are the characteristic features of LELC. Immunohistochemical studies revealed that the tumor cells were positive for cytokeratin 19 but were negative for glypican 3. In situ hybridization using EBV-encoded RNA was negative. Therefore, a diagnosis of ICC with LELC components not associated with EBV was made. Because there is limited information available regarding the prognosis and treatment of ICC with LELC components because of the limited number of reported cases, additional studies will be needed to clarify the clinicopathologic features of this disease.

Oral environment and cancer

Cancer is now the leading cause of death in Japan. A rapid increase in cancer mortality is expected as Japan is facing a super-aged society. Many causes of cancer are known to be closely linked to life style factors, such as smoking, drinking, and diet. The oral environment is known to be involved in the pathogenesis and development of various diseases such as bronchitis, pneumonia, diabetes, heart disease, and dementia. Because the oral cavity acts as the bodily entrance for air and food, it is constantly exposed to foreign substances, including bacteria and viruses. A large number of bacteria are endemic to the oral cavity, and indigenous oral flora act to prevent the settlement of foreign bacteria. The oral environment is influenced by local factors, including dental plaque, tartar, teeth alignment, occlusion, an incompatible prosthesis, and bad lifestyle habits, and systemic factors, including smoking, consumption of alcohol, irregular lifestyle and eating habits, obesity, stress, hormones, and heredity. It has recently been revealed that the oral environment is associated with cancer. In particular, commensal bacteria in the oral cavity are involved in the development of cancer. Moreover, Candida, human papilloma virus and Epstein-Barr virus as well as commensal bacteria have been reported to be associated with the pathogenesis of cancer. In this review, we introduce recent findings of the correlation between the oral environment and cancer.

Epstein-Barr Virus in Gastric Carcinomas from Singapore

One hundred and thirty-seven consecutive cases of gastric carcinomas were evaluated for the presence of Epstein-Barr virus (EBV) by use of an in situ hybridization (ISH) assay for EBV-encoded RNA (EBER1) transcript and by means of the polymerase chain reaction (PCR) to amplify the internal repeat segment of the EBV genome. EBER1 was localized in tumor nuclei of 6 (4.3%) specimens, 5 of which were lymphocpithclioma-like carcinomas. Forty-five cases (32.8%) were positive by PCR, but evidence suggests that EBV positivity in many of these cases was due to latently infected lymphocytes. The presence of EBV by ISH was strongly associated with increased lymphocytic infiltration of tumors. Our inability to identify significant correlations between EBV-infected tumors and patient age, gender, or ethnicity, and tumor stage or histologic type was partly thwarted by low numbers of ISH-positive cases. Int J Surg Pathol 4(3):00-00, 1997

Lack of Evidence of Pathogenetic Role of Epstein-Barr Virus in Thymic Lymphoid Hyperplasia and Thymomas in the Chinese Population of Hong Kong

A previous study from Hong Kong by McGuire et al. reported frequent demonstration of Epstein-Barr virus (EBV) DNA by Southern blot analysis in thymoma, thymic lymphoepithelioma-like carcinoma, and thymic lymphoid hyperplasia. This provoca tive finding, however, could not be confirmed by studies in the Western populations using the Southern blot technique and/or polymerase chain reaction to detect EBV- DNA or in situ hybridization to detect EBV encoded RNA (EBER), raising the possibility that the association with EBV may be restricted to Asians. This study was performed to clarify this issue by using a highly sensitive localization technique for EBER on a larger series from the Asian population of Hong Kong. Paraffin sections obtained from 10 cases of thymic lymphoid hyperplasia, 42 noninvasive thymomas (including one case previously reported to be EBV positive), 11 invasive thymomas, and 9 thymic carcinomas (including 5 cases of lymphoepithelioma-like carcinoma) were studied. EBER signal was not detected in the epithelial cells in any of the cases except for two cases of lymphoepithelioma-like carcinoma. In two thymomas, a few small lympho cytes (<0.1%) were EBER positive. Failure to detect EBER was not an artifact due to RNA denaturation, because preserved mRNA could be demonstrated by oligo-dT labelling in 56 of the 72 cases. Thus, the results of this study on Hong Kong Chinese are in keeping with those reported in Caucasians, and more recently in Japanese and Taiwan Chinese, in that there is no association of EBV with thymic lymphoid hyperpla sia or thymoma, and that EBV may be demonstrated in a proportion of thymic lymph oepithelioma-like carcinomas. The positive results previously reported cannot be ex plained, because the occasional EBV-carrying lymphocytes detected in rare cases of thymoma should be insufficient to give a positive EBV result by Southern blot tech nique. Int J Surg Pathol 2(1):17-22, 1994

Cytomorphologic characteristics and differential diagnoses of lymphoepithelial carcinoma of the parotid

INTRODUCTION

Lymphoepithelial carcinoma of the salivary gland is an extremely rare neoplasm and is challenging to diagnose by fine needle aspiration (FNA). There are rare reports on the cytopathologic features of lymphoepithelial carcinoma, which may be mistaken for other high-grade salivary gland neoplasm or a metastasis to the salivary gland.

MATERIALS AND METHODS

A retrospective review was undertaken of 7 cases of lymphoepithelial carcinoma of the parotid diagnosed on FNA with histologic confirmation from 4 major medical centers.

RESULTS

Cytomorphologic features of lymphoepithelial carcinoma include smears with moderate cellularity displaying a rich nonneoplastic population of lymphoplasmacytic cells admixed with tissue fragments of high grade, malignant undifferentiated epithelial cells with high nuclear to cytoplasm ratio, hyperchromasia, prominent nucleoli, and scant to abundant, indistinct cytoplasm.

DISCUSSION

Diagnostic pitfalls of lymphoepithelial carcinoma include metastatic squamous cell carcinoma, metastatic nasopharyngeal carcinoma, and other high grade primary salivary gland neoplasms. Recognizing this lesion may help guide clinicians to perform additional imaging studies to exclude a primary from other sites.

HPV Infection, but Not EBV or HHV-8 Infection, Is Associated with Salivary Gland Tumours

Benign and malignant salivary gland tumours are clinically heterogeneous and show different histology. Little is known about the role of human herpes virus 8 (HHV-8), Epstein-Barr virus (EBV), and human papillomavirus (HPV) infection in salivary gland neoplasms. We investigated the presence of the three viruses in formalin-fixed, paraffin-embedded tissue samples in a cohort of 200 different salivary gland tumours. We performed EBV-LMP-1 and HHV-8 and p16 immunohistochemistry, a specific chip based hybridization assay for detection and typing of HPV and a chromogenic in situ hybridization for EBV analysis. Only one case, a polymorphic low-grade carcinoma, showed HHV-8 expression and one lymphoepithelial carcinoma was infected by EBV. In 17 cases (9%) moderate or strong nuclear and cytoplasmic p16 expression was detected. The HPV type was investigated in all of these cases and additionally in 8 Warthin's tumours. In 19 cases HPV type 16 was detected, mostly in Warthin's tumour, adenoid cystic carcinoma, and adenocarcinoma NOS. We concluded that HHV-8 infection and EBV infection are not associated with salivary gland cancer, but HPV infection may play a role in these tumour entities.

A rare case of undifferentiated nonkeratinizing carcinoma of the lip mucosa

Undifferentiated nonkeratinizing carcinoma (UNC) is a poorly differentiated squamous cell carcinoma accompanied by a prominent reactive lymphoplasmacytic infiltrate that can occur in many anatomic sites. It shares morphologic features with undifferentiated nonkeratinizing nasopharyngeal carcinoma, in which a strong association with Epstein-Barr virus (EBV) has been noted. Among UNCs arising outside the nasopharynx, the linkage with EBV is variable; in particular, the few cases of UNC of the lip described thus far have been negative for EBV. This report describes a rare case of primary UNC of the lower lip mucosa in a 73-year-old man in whom molecular analysis for EBV showed some amount of viral DNA within the tumor. Surgical excision without adjuvant treatment was performed and the patient was alive without recurrence after 42 months of follow-up. This report presents a rare localization of UNC possibly related to EBV infection and with a good clinical outcome.

Ezrin expression and its phosphorylation in gastric carcinoma with lymphoid stroma and Epstein-Barr virus infection

Gastric carcinoma with lymphoid stroma (GCLS) is a unique variant of gastric carcinoma that represents prominent lymphocytic infiltration and is correlated with Epstein-Barr virus (EBV) infection. Ezrin expression and activation are crucial in tumor metastasis and induce cell migration of EBV-related nasopharyngeal carcinomas. Using immunohistochemical methods, the expression of total and phosphorylated ezrin (p-ezrin), Thr567, was examined in 104 GCLS cases, including 78 EBV-positive and 26 EBV-negative cases, as well as 29 non-GCLS cases. Positive ezrin expression was detected to be at markedly higher levels in GCLS compared to non-GCLS (P<0.0001). Furthermore, ezrin expression was detected to be at higher levels in EBV-positive compared to EBV-negative GCLS (P=0.0294). High expression of p-ezrin in GCLS was associated with positive lymph node metastasis (P=0.0187). In summary, these results demonstrated that ezrin overexpression is correlated with the histologic characteristics of GCLS and EBV infection. Phosphorylation of ezrin may, therefore, contribute to lymph node metastasis in GCLS.

A spectrum of basaloid morphology in a subset of EBV-associated "lymphoepithelial carcinomas" of major salivary glands

Nasopharyngeal carcinomas of the undifferentiated or lymphoepithelial type are most commonly seen in South East Asians. Identical tumors have also been described at a variety of other sites including lung, skin and salivary gland and have been referred to by a number of names including lymphoepithelial carcinoma (LEC). LECs of major salivary gland are extremely rare. They are particularly common amongst the Inuit populations of the arctic region including Greenland (Denmark), Canada and Alaska, as well as South East Asians. Within the Inuit group, this tumor represents the majority of all salivary gland carcinomas. Amongst primary LEC of major salivary gland, most cases reported in the literature have represented typical nasopharynx-like tumors. Variants of Epstein-Barr Virus (EBV) associated LEC have not been described previously, to the best of our knowledge. In this report, we describe 4 EBV-associated major salivary gland LECs with prominent basaloid morphology, which represent 22 % of a cohort of 18 salivary LECs from an Inuit population in Greenland. The features described in these cases raise a differential diagnosis of other basaloid tumors, particularly in light of the salivary gland location. A basaloid variant of LEC in major salivary gland should be recognized, especially in highly prone populations, to avoid misdiagnosis of other more common salivary tumors.

Non-Epstein-Barr virus associated lymphoepithelioma-like carcinoma of the inferior common bile duct

A carcinoma displaying undifferentiated features with dense lymphoplasmacytic infiltration is defined as a lymphoepithelioma-like carcinoma (LEC), and some of LEC is associated with Epstein-Barr virus (EBV). All of the 13 previously reported cases of LEC of the biliary system were intrahepatic in location. Herein, we describe the first case of LEC of the inferior common bile duct. A 68-year-old Japanese man, who had been previously treated for hepatocellular carcinoma using microwave coagulation therapy, was found to have tumors of the common bile duct and pancreas head. Histopathological study of the resected tumor showed solid or cohesive nests of large undifferentiated cells with irregular large vesicular nuclei and nucleoli. Around the tumor cell nests, dense lymphoplasmacytic infiltration was observed. Focal glandular differentiation (approximately 5%) was also present. These histopathological features corresponded morphologically to LEC. Immunohistochemically, the tumor cells were positive for cytokeratin (CK) 7, CK 19 and CA19-9, but negative for CK 20 and Hep Par 1. In situ hybridization for Epstein Barr virus early small RNAs disclosed no nuclear signal in tumor cells. Therefore, a diagnosis of non-EBV-associated LEC of the inferior common bile duct was made. Although the prognosis of the biliary LEC is thought to be better than that of conventional cholangiocarcinoma, the differences in prognosis between EBV-positive and -negative cases have not yet been established. Therefore, additional case studies will be needed to clarify the clinicopathological features of LEC of the biliary tract.

Pathobiology of selected tumors of the base of the skull

Skull base surgery is a new subspeciality, and, up to this point, most articles on this subject have focused on innovative operative-reconstructive approaches to tumors in this region. It is now important that we embark on a new era, the era of tumor biology, and concentrate on new ways of evaluating these neoplasms from a pathologic viewpoint. The hematoxylin-cosin section is no longer an end point, but just a beginning. This is the age of molecular biology. It is important that these tumors be evaluated, either prospectively or retrospectively, employing immunohistochemical staining, flow cytometry, oncogene expression, cytogenetics, or other techniques in order to identify important prognostic features. Data from these additional studies may then be used to develop new treatment strategies. Skull base societies should develop protocols for one or more of these tumors to ensure that they are indeed evaluated uniformly. In this article I emphasize the importance of accurate histologic classification or subclassification of these neoplasms and focus on contemporary parameters that may or may not impact on prognosis.

Lymphoepithelial-like carcinoma of the oropharynx: a morphologic variant of HPV-related head and neck carcinoma

Human papillomavirus-associated squamous cell cancer of the head and neck (HPV-HNSCC) represents an important subgroup of head and neck cancer that is characterized by distinct epidemiologic, clinical, and pathologic features including a relatively constant microscopic appearance. For those cancers that deviate from the morphologic prototype, an association with HPV may not be recognized and accurate tumor classification may not be achieved. We have identified 22 cases of HPV-HNSCC with well-developed lymphoepithelial features including tumor cells with syncytial cytoplasm, vesicular nuclei, and large central nucleoli dispersed in an inflammatory background as cell clusters or single cells. The pattern closely resembles Epstein-Barr virus (EBV)-induced undifferentiated carcinoma of the nasopharynx. Indeed, 3 of the carcinomas presenting as lymph node metastases were originally misdiagnosed as metastatic nasopharyngeal carcinoma. Unlike nasopharyngeal carcinoma, the cases were of oropharyngeal origin, p16 positive by immunohistochemistry (22 of 22, 100%), HPV-16 positive by in-situ hybridization (19 of 22, 86%), and EBV negative by in-situ hybridization (21 of 21, 100%). Like conventional HPV-related HNSCC, the cases tended to occur in patients below 60 years of age (77%), men (73%), and nonsmokers (59%). For carcinomas of the head and neck that exhibit lymphoepithelial features, one cannot assume an EBV-driven process by morphology alone. HPV testing has disclosed a previously unrecognized morphologic variant of HPV-HNSCC that is microscopically indistinguishable from EBV-related carcinoma. For lymphoepithelial carcinomas presenting as cervical lymph node metastases, testing for HPV and EBV is mandatory.

Epstein-barr virus-associated lymphoepithelioma-like carcinoma of mandible

We describe the first case of an lymphoepithelioma-like carcinoma (LEC) of the mandible with a view to discuss probable histogenesis from salivary gland inclusions in the mandible, effective therapy, the unusual pattern of nodal metastases, and association with the Epstein-Barr virus. An 11-year-old boy presented with a lytic lesion in the left mandible and bilateral neck node enlargement. Histologically, the biopsied metastatic neck nodes showed sinusoids distended with histiocytes and single large atypical cells that mimicked Hodgkin lymphoma. The mandibular tumor on biopsy showed morphology similar to an undifferentiated carcinoma or LEC of nasopharynx with nuclear Epstein-Barr virus-associated in situ hybridization signals. The patient received ifosfamide, cisplatin, and etoposide chemotherapy followed by a hemimandibulectomy, which did not reveal any residual tumor. Postoperative radiotherapy was completed, and 3 years later the patient is alive and free of disease.

[Sinonasal basaloid squamous cell carcinoma in biopsies of inverted papilloma]

Basaloid squamous cell carcinoma (BSCC) is a rare tumor representing an aggressive variant of squamous cell carcinoma (SCC) and arising from a common precursor cell. BSCC rarely originates from the sinonasal tract. We report on an 83-year-old woman with BSCC after multiple resections of an inverted papilloma (IP) of the left sinonasal tract. The tumor filled the nasal cavity completely and was infiltrating the ipsilateral frontal skull base and periorbita. Because of the tumor's expansion, the patient's age, and comorbidity, surgery was not performed, but primary radiotherapy was initiated. A possible association between sinonasal BSCC and IP, as implicated by the current case, must be further investigated. In any case, IP requires consequent endoscopic and, if necessary, radiological follow-up in order to detect recurrent disease or malignant transformation.

Association of Epstein-Barr Virus with Nasopharyngeal Carcinoma and Current Status of Development of Cancer-derived Cell Lines

It is well known that the Epstein-Barr virus (EBV) contributes directly to tumourigenesis in nasopharyngeal carcinoma (NPC), primarily in the undifferentiated form of NPC (WHO type III; UNPC or UC), which is commonly found in South East Asia. Unfortunately, research in NPC has been severely hampered by the lack of authentic EBV-positive (EBV+) human NPC cell lines for study. Since 1975, there have been more than 20 reported NPC cell lines. However, many of these NPC-derived cell lines do not express EBV transcripts in long-term culture, and therefore that finding may dispute the fundamental theory of NPC carcinogenesis. In fact, currently only one EBV+ human NPC cell line (C-666) in long-term culture has been reported. Hence, most of the NPC cell lines may not be representative of the disease itself. In order to better understand and treat NPC, there is an urgent need to develop more EBV+ human NPC cell lines. In this review, we discuss the authenticity of existing NPC cell lines and the impact of our understanding of NPC biology on the treatment of the disease and the relationship of EBV to NPC in the context of cell lines. Key words: Carcinogenesis, Cell culture, Epstein-Barr virus, Hayflick’s limit

A rare case of lymphoepithelial carcinoma of the lip

Lymphoepithelial carcinoma (LEC) is a rare category of malignant neoplasms that share morphologic features with undifferentiated nasopharyngeal carcinoma, which can be regarded as the prototype Epstein-Barr virus (EBV)-positive epithelial neoplasm. A similar association with EBV is emerging for LEC of the oral cavity, which appears to be strongly influenced by the ethnic origin of the patient. A rare case of primary LEC of the lower lip in a 73-year-old Caucasian man is described. The tumor showed a striking microscopic resemblance to undifferentiated nasopharyngeal carcinoma (lymphoepithelioma) with features of a syncytial growth pattern, large undifferentiated tumor cells with vesicular nuclei, prominent eosinophilic nucleoli, and a dense intratumoral lymphocytic infiltrate. There was, however, no evidence of EBV infection of the tumor cells by immunohistochemistry and polymerase chain reaction, suggesting that EBV probably does not play a role in the pathogenesis of LEC of the lip in Caucasian patients.

Lymphoepithelioma-like cholangiocarcinoma not associated with EBV

Reported herein is an unusual case of intrahepatic cholangiocarcinoma with lymphoepithelioma-like appearance in a 64-year-old man who was found to have an intrahepatic mass without cirrhosis. The tumor had two distinct histological patterns with dense lymphoplasmacytic infiltrate. The first was similar to nasopharyngeal undifferentiated carcinoma; the second pattern was a well-differentiated adenocarcinoma. Transition between the two components was observed in the same duct. Immunohistochemistry indicated that the tumor was immunoreactive with AE1/AE3 and cytokeratin (CK) 7, but negative for CEA and CK20. Stromal inflammatory infiltrate primarily consisted of plasma cells and lymphocytes. Immunohistochemical examination and in situ hybridization for EBV showed no integration of the virus in the tumor cells. Intrahepatic lymphoepithelioma-like carcinoma is rare, and most are associated with EBV. Only three cases were not associated with EBV. The authors would like to add one more example of the tumors not associated with EBV.

Association of Hodgkin's lymphoma with Epstein Barr virus infection

The role of Epstein Barr virus (EBV) in the onset of Hodgkin's lymphoma has been a subject of ongoing research. However, confirmation of EBV oncogenic involvement was not possible due to the small number of neoplastic cells characteristic for this type of tumor. Presence of EBV infection in neoplastic and non-neoplastic cells was analyzed in 81 cases of Hodgkin's lymphoma. In neoplastic cells, using an immunohistochemical method, latent membrane protein 1 (LMP1) was found in 33,3% of cases, while in situ hybridization results demonstrated the presence of EBER RNA in 48,1% of the cases. EBER RNA was found in non-neoplastic lymphocytes in 38,3% of cases. EBV is most frequently associated with Hodgkin's lymphoma in the first and seventh decade of life, specifically the nodular sclerosis subtype. No apparent difference was observed in the association of Hodgkin's lymphoma with EBV between genders, or in relation to clinical stage of the disease and average age of the patient. However, association with childhood age is significantly greater in comparison to adults. EBV associated disease shows a significantly greater prevalence in T lymphocytes. Slightly more abundant are cytotoxic T lymphocytes, which are also more frequently in contact with Reed-Sternberg cells, although there is no difference in number and positioning of histiocytes. Variations between the data on the association of EBV with Hodgkin's lymphoma among studies from different parts of the world suggest that factors of age, gender, ethnic background and social status might present biological modifiers of EBV influence on the pathogenesis of this neoplasm. The differences in non-neoplastic infiltrate EBV+ and EBV- lymphoma indicate the effect of the virus on the immune interaction of tumor and host in this disease.

Lymphoepithelial carcinoma of the parotid gland: is an association with Epstein-Barr virus possible in non-endemic areas?

Lymphoepithelial carcinoma (LEC) is a rare histological type of cancer of the salivary glands. Here is reported a case of LEC of the parotid gland that developed in a Caucasian female, whose serology was positive for Epstein-Barr virus antibody. The patient underwent surgical treatment and postoperative radiotherapy. Because of the relatively limited clinical data concerning LEC of the salivary glands compared to other more common histological types, the clinical course, optimal treatment and prognosis have not been extensively studied. The aim of this report was to summarize all the key points, following a comprehensive literature review.

Lymphohistiocytoid Variant of Malignant Mesothelioma of the Pleura: A Series of 22 Cases

The lymphohistiocytoid variant of diffuse malignant mesothelioma is rare with very few cases described in the literature. It is characterized by mesothelial cells with a histiocytelike appearance and an associated dense lymphoid infiltrate. We studied clinicopathologic features and immunohistochemical patterns of a series of 22 cases. The histiocytelike cells had a mesothelial immunophenotype: AE1/AE3 (100%), calretinin (100%), CK5/6 (46%), and EMA (52%). The prominent lymphoid component showed a cytotoxic T-cell immunophenotype. Prognosis was similar to that of a large series of epithelioid diffuse malignant mesotheliomas. Formely, it was classified within the sarcomatoid type. We suggest that it should be reclassified as an epithelioid variant because of its similar behavioural characteristics. There was no evidence of Epstein-Barr virus-related infection.

Lymphoepithelioma-like carcinoma of the skin with spindle cell differentiation

BACKGROUND

Primary cutaneous LELC is a cutaneous neoplasm with histopathologic features identical to those seen in the undifferentiated subtype of nasopharyngeal carcinoma. It is extremely rare, with only approximately 30 cases reported in the literature.

METHODS

We report a case of primary cutaneous LELC arising on the forehead of a 72 year-old male in which a proportion of the neoplastic cells demonstrated distinctive spindle cell morphology.

RESULTS

Microscopic examination showed a dense lymphoplasmacytic infiltrate admixed with large spindle-shaped cells with vesicular nuclei, prominent nucleoli, and frequent mitotic figures. These cells were negative for an extensive panel of immunohistochemical markers and positive only for broad-spectrum cytokeratins and epithelial membrane antigen. There was no connection between the tumor and the epidermis and no epidermal dysplasia. In situ hybridization for Epstein-Barr virus was negative.

CONCLUSIONS

The spindle cell differentiation in this case is unusual and suggests that in some cases the differential diagnosis of cutaneous spindle cell neoplasms might include primary cutaneous LELC.

Diagnostic application of Epstein-Barr virus-encoded RNA in situ hybridisation

AIMS

Epstein-Barr virus (EBV) has been implicated in the pathogenesis of nasopharyngeal carcinoma and a range of proliferative lymphoid conditions. In situ hybridisation (ISH) looking for virus-encoded RNA (EBER) transcripts is performed simply using a commercially available probe. We aimed to examine the application of this test in a routine diagnostic setting.

METHODS

In total, 26 cases in which EBV ISH was requested for diagnostic purposes were examined. We looked at the indication for testing, the result and its implication for the final diagnosis.

RESULTS

Cases were classified into three categories: possible nasopharyngeal carcinoma; possible EBV-related lymphoma; and possible immunodeficiency-associated lymphoproliferative disorder. Six of nine cases of possible nasopharyngeal carcinoma were EBV ISH positive (3/3 primary and 3/6 secondary), confirming the diagnosis. Three of 14 possible lymphoma cases were EBV ISH positive which, along with appropriate ancillary tests, assisted in making the diagnoses of Burkitt's lymphoma, lymphomatoid granulomatosis and extranodal NK/T-cell lymphoma of nasal type. All of three immunodeficiency-associated cases were EBV ISH positive. Two of these were post-transplant lymphoproliferative disorders, monomorphic type. The third case was classified as HIV-related polymorphic lymphoproliferative disorder.

CONCLUSIONS

In our experience, EBV ISH is a straightforward and rapid procedure to perform, giving unequivocal results. Used in the appropriate clinicopathological setting it can be a highly useful ancillary diagnostic aid.

Hepatocellular lymphoepithelioma-like carcinoma associated with epstein barr virus: a hitherto unrecognized entity

OBJECTIVE

Lymphoepithelioma-like carcinoma (LELC) is an undifferentiated carcinoma with a dense lymphoid stroma. It has been reported in diverse organs and shows variable association with Epstein-Barr virus (EBV). Only a few EBV positive cases have been observed in the hepatobiliary system, all of which were considered to be cholangiocarcinomas. We report a unique case of hepatocellular LELC arising in a cirrhotic liver with EBV demonstrated in the tumor cells.

METHODS AND RESULTS

A 39-year-old Hispanic female underwent an orthotopic liver transplant for end stage liver disease secondary to chronic hepatitis C. A high-grade hepatocellular carcinoma with a dense lymphocytic infiltrate was found in the explant as well as in a portal lymph node. Three months posttransplant, the patient developed numerous hepatic nodules with enlarged periaortic and portacaval lymph nodes. Biopsy of the hepatic nodules showed a recurrent hepatocellular carcinoma devoid of a dense lymphocytic infiltrate. Both the primary and recurrent tumors were positive for EBV by molecular studies. The patient eventually expired from liver failure over a 6-week period.

CONCLUSION

This case represents the first report of EBV-positive hepatocellular LELC. It is particularly interesting given the precipitous clinical outcome, which was possibly related to immunosuppresive therapy.

Basaloid squamous cell carcinoma of the head and neck

PURPOSE OF REVIEW

Basaloid squamous cell carcinoma is an uncommon variant of squamous cell carcinoma and was first described as a distinct entity in 1986. Basaloid squamous cell carcinoma seems to have a poorer survival rate than classical squamous cell carcinoma. On the basis of a critical literature survey, we attempt to evaluate if basaloid squamous cell carcinoma is really more aggressive and presents a poorer outcome than squamous cell carcinoma.

RECENT FINDINGS

All papers are retrospective, and most include small numbers of cases, which are further diminished when subdivided according to specific sites. Only in three studies was basaloid squamous cell carcinoma of the head and neck region compared with matched squamous cell carcinoma controls. These studies did not show a uniform tendency regarding the aggressiveness and outcome of basaloid squamous cell carcinoma. In addition, several recent papers confirmed the presumed greater aggressiveness and worse outcome, and other recent papers questioned these characteristics.

SUMMARY

The presented literature survey does not permit conclusions regarding the aggressiveness and outcome of basaloid squamous cell carcinoma compared with squamous cell carcinoma. Greater numbers of basaloid squamous cell carcinoma should be studied and compared with site-matched, stage-matched, and age-matched controls of conventional squamous cell carcinoma.

Epstein-Barr virus-associated lymphoepithelioma-like carcinoma of the esophagus

Epstein-Barr virus (EBV)-associated lymphoepithelioma-like carcinoma (LELC) rarely occurs in the esophagus. We report a case of such tumor arising in the esophagus of a 64-year-old Taiwanese woman. No tumors were detected outside the esophagus including nasopharynx by thorough clinical studies. She underwent subtotal esophagectomy. Light microscopy disclosed a poorly differentiated carcinoma morphologically reminiscent of nasopharyngeal undifferentiated carcinoma (lymphoepithelioma). Immunohistochemical stain for latent membrane protein-1 showed positivity on the tumor cells. The infiltrating lymphocytes were chiefly composed of CD8-positive cytotoxic T cells. EBV DNA was demonstrated by both nested polymerase chain reaction (PCR) in the main tumor and metastatic lymph node, and localization in the tumor cells by in situ PCR in situ hybridization (ISH). However, the result of EBV-encoded small RNA-1 ISH was negative. Our case suggests that LELC of the esophagus may be associated with EBV in the endemic area. Due to its distinct histological features, the association with EBV, and possible prognostic implication, LELC of the esophagus should be precisely diagnosed and discerned from the usual poorly differentiated carcinoma.

Expression of Epstein-Barr virus-encoded small nuclear RNA 1 in Japanese nasopharyngeal carcinomas

An examination was made of the incidence of the Epstein-Barr virus (EBV) genome and its exact localization in 39 cases of nasopharyngeal carcinoma (NPC) in Japanese patients by means of in situ hybridization (ISH) with a digoxigenin-labeled Epstein-Barr virus-encoded small nuclear RNA 1 (EBER1) oligonucleotide probe. Hybridization signals were observed in the nucleus of tumor cells in all 39 NPCs, including keratinizing carcinomas. The signals varied greatly in intensity from case to case and even from cell to cell in the same tumor, but were recognized in most tumor cells in each case. Signals could occasionally be seen in limiting number of infiltrating small lymphocytes but were absent in all tumors of the tongue, midpharynx and hypopharynx. Combined immunohistochemistry-ISH studies indicated that EBER1 signals were restricted to tumor cells positive for cytokeratin. As a result of this study, it is now possible to perform large-scale retrospective analyses using routine formalin-fixed, paraffin-embedded tissue sections and to combine ISH for the EBV genome with immunohistochemistry for cytokeratin to determine the epithelial features of EBV genome-possessing cells. All NPCs were clearly shown to be EBV-infected, thus indicating that EBV is essential for the oncogenesis of NPCs.

Pathogenic roles for Epstein-Barr virus (EBV) gene products in EBV-associated proliferative disorders

Epstein-Barr virus (EBV) is associated with a still growing spectrum of clinical disorders, ranging from acute and chronic inflammatory diseases to lymphoid and epithelial malignancies. Based on a combination of in vitro and in vivo findings, EBV is thought to contribute in the pathogenesis of these diseases. The different EBV gene expression patterns in the various disorders, suggest different EBV-mediated pathogenic mechanisms. In the following pages, an overview of the biology of EBV-infection is given and functional aspects of EBV-proteins are discussed and their putative role in the various EBV-associated disorders is described. EBV gene expression patterns and possible pathogenic mechanisms are discussed. In addition, expression of the cellular genes upregulated by EBV in vitro is discussed, and a comparison with the in vivo situation is made.

Detection of human viruses in patients with chronic periodontitis and the relationship between viruses and clinical parameters

BACKGROUND

Recent studies have demonstrated that various human viruses, especially cytomegalovirus (HCMV), Epstein-Barr virus type-1 (EBV-1), and herpes simplex virus (HSV), seem to play a part in the pathogenesis of human periodontitis. Little information is available on the relationship between these viruses and clinical periodontal parameters in patients with chronic periodontitis. This study examined the occurrence of HCMV, EBV-1, and HSV in patients with chronic periodontitis and the relationship between these viruses and clinical parameters.

METHODS

A nested polymerase chain reaction (PCR) method determined the presence of HCMV, EBV-1, and HSV. Subgingival plaque samples from 30 patients with chronic periodontitis and 21 randomly selected healthy controls were collected by paper points, and clinical measurements were recorded from both sampling sites and entire dentition. The following indices were measured: plaque index (PI), gingival index (GI), probing depth (PD), and clinical attachment loss (CAL).

RESULTS

HCMV was detected in 44.3% of chronic periodontitis patients and 14.3% of healthy persons (P < 0.05); EBV-1 in 16.7% of chronic periodontitis patients and 14.3% of healthy persons (P = 1.00); and HSV in 6.7% of chronic periodontitis patients and in no healthy persons. HCMV and EBV-1 detected and undetected sites in patients with periodontitis showed statistically significant differences in sampling clinical depth (SPD) and sampling clinical attachment loss (SCAL). Differences in the measurements of PI of entire dentition and GI of entire dentition between HSV detected and undetected sites were statistically significant.

CONCLUSIONS

Findings of the present study confirm the frequent presence of HCMV in crevicular samples of chronic periodontitis lesions, and suggest a strong relationship between the presence of HCMV and EBV-1 in subgingival areas and the measurements of probing depth and probing attachment loss.

Lymphoepithelioma-like carcinoma of the uterine cervix

CONTEXT

It has been proposed that Epstein-Barr virus (EBV) plays a role in the etiology of lymphoepithelioma-like carcinoma (LELC) in diverse anatomic locations. In contrast to Asian women, Western women have a low prevalence of LELC of the uterine cervix, and EBV genomes have not been identified.

OBJECTIVE

To assess the presence of EBV in LELC of the uterine cervix in 4 white Western women.

DESIGN

We collected 4 cases of LELC of the uterine cervix between 1990 and 2000. We performed histologic and immunohistochemical analyses of formalin-fixed, paraffin-embedded tumor samples. We amplified tumor DNA with polymerase chain reaction to detect EBV, human papillomavirus, and simian virus 40 DNAs.

RESULTS

Immunohistochemically, tumor cells were positive for cytokeratins and showed strong expression of p53 and MIB-1. Staining for the oncoprotein c-Erb-B2 was focally positive, and staining for Bcl-2 and progesterone receptors was negative. Only one case showed focal nuclear staining for estrogen receptors. All cases had a dense infiltrate of mature lymphocytes expressing T-cell antigens CD45RO, CD3, and CD8. Polymerase chain reaction analysis did not detect EBV, human papillomavirus, or simian virus 40 DNA sequences in any of the 4 cases. One case had positive serologic results for anti-EBV antibodies, indicating a mild or chronic infection.

CONCLUSIONS

LELC of the uterine cervix shows the immunohistochemical profile of an aggressive tumor in spite of its good prognosis, in which CD8 cytotoxic suppressor lymphocytes could play an important role. Based on our results, the role of EBV, human papillomavirus, or simian virus 40 in the pathogenesis of LELC of the uterine cervix in Western women remains unclear.

A case of lymphoepithelioma-like carcinoma arising from the palatine tonsil

Lymphoepithelioma is the designation that has been given to describe undifferentiated squamous cell carcinoma variants of nasopharyngeal neoplasms (World Health Organization type 3), and a strong association with Epstein-Barr virus (EBV) infection has been established. Outside the nasopharynx, lymphoepithelioma-like carcinomas (LEC) are exceedingly rare in other head and neck lesions. This report features a rare case of LEC of the palatine tonsil occurring in a 60-year-old Japanese man who presented with a three-month history of a neck mass. The surface of tonsils were smooth, not ulcerated macroscopically, and the ipsilateral tonsil showed only slight enlargement on radiological findings. Diagnosis of lymphoepithelioma was finally made based on the pathological review of the tonsillectomy specimens, preceded by a cervical lymph node biopsy. The patient was treated with irradiation and adjuvant chemotherapy. RNA in situ hybridization as well as polymerase chain reaction (PCR) techniques, and serological testing did not demonstrate an association with EBV infection. The clinical presentation, pathological features and association with EBV are described with a review of the literature.

Lymphoepithelioma-like carcinoma of oral cavity: report of three cases and literature review

Lymphoepithelioma-like carcinoma is a rare tumour in the oral cavity and is characterized histologically by non-keratinizing, undifferentiated squamous cell carcinoma with lymphocytic infiltration. Three consecutive cases of intraoral lymphoepithelioma-like carcinoma are reported. A review of the literature reveals a similar biological behaviour to that of nasopharyngeal lymphoepithelioma: a high incidence of cervical nodal spread and remarkable radiosensitivity. Chemotherapy should be considered when nodal or distant metastases are present. The association of the Epstein-Barr virus with this tumour remains unclear but our experience suggests a positive correlation in Chinese individuals.

Tissue specific distribution of Epstein-Barr virus (EBV) BZLF1 gene variants in nasopharyngeal carcinoma (NPC) bearing patients

Using EBV BNLF1 gene polymorphism, we have recently shown that, in NPC bearing patients, lymphocytes and tumor cells of the same individual were infected by different viruses. It appeared as a rule that EBV infection was by multiple strains in these immunocompetent, HIV negative patients. Our data did not detect any evident association between tumor cells and a particular BNLF1 variant. In the present paper, we extend our analysis to the BZLF1 gene of the viruses present in different sites of the same patients. Only two main variants of the BZLF1 gene were identified. Despite this very weak polymorphism of this locus, our results entirely confirm the very frequent occurrence of multistrain infections in these patients, and the presence of different EBV strains in tumor cells and lymphocytes from the same individual. However, in contrast to our results concerning the BNLF1 gene, the BZLF1 variants appeared to be cell type specific, one being associated mainly with epithelial or tumor cells and the other with lymphocytes. The possible reasons for this distribution are discussed.

Malignant Lymphoepithelial Lesion of the Parotid Gland: A Case Report and Review of the Literature

Malignant lymphoepithelial lesions are rare tumors of the major salivary glands. They most often occur in Asians and Greenland Eskimos and are strongly associated with Epstein-Barr virus infection. We report a case of a malignant lymphoepithelial lesion of the parotid gland that developed in an Italian-American woman whose serology was positive for Epstein-Barr virus antibody. The patient underwent a left total parotidectomy and upper neck dissection, followed by radiation therapy. At the 2-year follow-up, she remained free of disease.