Malignant lymphoepithelial lesion

A case of undifferentiated carcinoma arising from benign lymphoepithelial lesion (BLEL) of the parotid gland was studied by light and electron microscopy. Histopathologically, the carcinoma was composed of pleomorphic anaplastic cells showing an undifferentiated type among abundant lymphoid tissue forming germinal center. Among the prominent lymphoid tissue, epithelial hyperplasia, dysplasia, and squamous metaplasia of the duct epithelium were found. Dysplastic epithelium revealed a transition with carcinomatous component in some areas. On the electron microscopic observation, the tumor cells were poorly differentiated, possessing desmosomes and intracytoplasmic filaments. The patient is alive and well 2 months after resection of the tumor, but has a high titer of serum Epstein-Barr virus capsid antigen in IgG. Eighty five cases of the malignant lymphoepithelial lesion (MLEL) including the present case are summarized.     

Benign lymphoepithelial salivary lesion to be distinguished from adenolymphoma

In a collection of 11 cases, the benign lymphoepithelial lesion presented clinically in every case as a tumour of a salivary gland. In eight cases the parotid was affected, in two a palatal salivary gland, and in one the submandibular gland was affected. Microscopically the lesion consisted of a mixture of lymphoid and epithelial components and, although the appearances in several cases suggested lymphosarcoma or reticulosarcoma, the arrangement of the epithelial component in characteristic islands (epi-myoepithelial islands) indicated the benign nature of the lesion. In one case incomplete excision of a lesion of the palate was followed by a recurrence that was cured by a radium mould.     

Cystic benign lymphoepithelial lesion of the salivary glands in HIV-positive patients

Summary Two cases of cystic benign lymphoepithelial lesions (CBLL) of the submandibular and parotid glands occurring in HIV-positive patients are reported. The clinical and pathological criteria are defined and the differences from Sjögren's syndrome discussed. The presence, in the epithelial component, of T-cells labelled by the human mucosal lymphocyte antibody argues for a primary involvement of epithelial structures in CBLL, the lymphoid hyperplasia occurring secondarily.     

Benign lymphoepithelial lesion (Mikulicz's disease) of the salivary gland: An ultrastructural study

An ultrastructural study of a benign lymphoepithelial lesion of the parotid gland demonstrated that the so-called epimyoepithelial cell islands were sharply demarcated from the surrounding parenchyma by a thick basement membrane containing collagen fibers. The hyaline material seen by light microscopy within the islands was ultrastructurally similar in appearance to this delimiting basement membrane. The epithelial cells within the islands were united by well formed desmosomes and many had prominent tonofilament bundles, but myogenic differentiation was not observed. Hydropic degeneration was not seen in these epithelial cells; cells with a perinuclear clear space seen by light microscopy corresponded to large lymphoid cells ultrastructurally.     

Benign lymphoepithelial lesion of the parotid gland in intravenous drug users

Fifteen partial parotid salivary gland resection specimens interpreted as benign lymphoepithelial lesion (BLL) were accessioned by our surgical pathology service between January 1983 and December 1986. Twelve of the specimens were removed from 11 prison inmates referred to our hospital, a patient subgroup constituting the source of only 2% of surgical pathology specimens in general. All prison inmates with BLL had a history of intravenous drug use, had developed unexplained lymphadenopathy concurrently with the parotid gland enlargement, and had suspected human immunodeficiency virus (HIV) infection (serologically confirmed in two). Histopathologic features of the parotid gland specimens included atypical follicular hyperplasia and follicular involution, resembling lymph node changes of HIV infection. The clinical and pathologic findings in these cases suggest an association between HIV infection and BLL, and support a previously proposed mechanism for the development of BLL through progressive enlargement of intraparotid lymph nodes.     

Sporadic EBV-associated lymphoepithelial salivary gland carcinoma with EBV-positive low-grade myoepithelial component

Salivary gland lymphoepithelial carcinomas (LECs) are associated with Epstein–Barr virus (EBV) in endemic areas, whereas sporadic cases are usually EBV negative. We have studied two EBV-associated LECs from Caucasian patients for their EBV gene expression profile and their immunophenotype. Tumour cells of case 1 showed expression of EBNA1 only, corresponding to an EBV latency type I. Tumour cells of this case expressed various basal and glandular cytokeratins. In case 2, the LEC was accompanied by a low-grade spindle cell lesion with an immunophenotype of myoepithelial cells, whereas the high-grade tumour expressed cytokeratin (Ck) 8 only. In case 2, the high-grade tumour showed an EBV lantency II pattern with expression of EBNA1, LMP1 and LMP2A (latency II). The spindle cell lesion of this case was also EBV-infected and showed low levels of EBNA1 and LMP1 expression, while LMP2A was not detectable. The detection of EBV in both components of case 2 together with immunophenotypic evidence of transition between both components supports the notion that at least some LECs arise through a low-grade myoepithelial intermediate. Expression of LMP2A may be of therapeutic interest because it may make such cases amenable to immunotherapy with EBV-specific cytotoxic T cells.     

Malignant lymphoma of parotid associated with Mikulicz disease (benign lymphoepithelial lesion)

Benign lymphoepithelial lesion (Mikulicz disease) is generally regarded as an inflammatory disorder of unknown aetiology, characterized by epimyoepithelial islands, and unrelated to malignant lymphoma. Five cases have been collected which show evidence at the same site of both Mikulicz disease and a malignant lymphoma. The latter took the form of reticulum-cell sarcoma or Hodgkin's disease. The two diseases were discovered simultaneously or the malignant lymphoma was detected at a subsequent date. The probable sequence of events is discussed. These cases are regarded as one of the best illustrations in man of an autoimmune disorder being followed by the development of malignant lymphoma. It is concluded that so-called benign lymphoepithelial lesion is not always innocuous and an attempt is made to establish histological criteria which might be regarded with suspicion in a particular case.     

Malignant myoepithelioma of minor salivary gland origin.

Myoepithelial cells are a significant component of most types of salivary gland tumors. A small but increasing number of case reports have also shown that true myoepithelioma (ME) forms a distinct clinicopathologic entity of salivary gland tumors with unique histologic features, however, the malignant type of ME is exceedingly rare. The present paper reports a case of malignant ME originating from the palatal minor salivary gland. The patient was a 70-year-old Japanese male with recurrent tumor of the palatal region. Pathologically, the tumor consisted of proliferating polygonal-shaped cells and plump spindle cells with cellular atypia and frequent mitoses, forming lumen-less lobuli or strands. Clear tumor cells were also found in part. The stroma was poorly developed without any myxoid or chondroid features. Immunohistochemical study showed positive stainings for S-100 protein, actin and vimentin in the tumor cells. Ultrastructurally, tumor cells had features of myoepithelial cells.     

Malignant salivary gland tumors: role of radiation therapy

Malignant salivary gland tumors are rare. They represent less than one percent of all head and neck tumors. Approximately three fourths of all salivary gland tumors occur in the major salivary glands.     

Malignant lymphomas of the salivary glands. Review of the literature and report of 33 new cases, including four cases associated with the lymphoepithelial lesion.

Malignant lymphomas involving major salivary glands have been reported to occur in 31 cases. To these, we add 33 cases, 17 of which were studied in detail from the points of view of clinical presentation, classification (Rappaport), staging (Ann Arbor), therapy, and subsequent course. The parotid gland was involved much more frequently than the submandibular gland. No example of sublingual gland involvement was discovered in the present series. Most of the patients were in the sixth and seventh decades of life. Noteworthy is that all sub-types of lymphosarcoma were encountered, with only a single case of Hodgkin's disease present. In four of the patients, the characteristic histologic picture of lymphoepithelial lesion was found in juxtaposition to malignant lymphoma. The majority of patients received one or more courses of postoperative radiotherapy, which offered the best chance for long-term remission. However, only 40% of patients were free of disease after two years.     

Synchronous benign epithelial tumors arising in the palatal minor salivary gland. First report of an unusual minor salivary gland lesion

A review of the literature shows that unilateral benign salivary gland tumors of different histologic types in a single gland are so rare as to be curiosities, and all of such reported tumors have arisen in the parotid gland. The present paper reports a case of synchronous benign epithelial tumors of different histologic type arising in the palatal minor salivary gland of a 57-year-old woman who had first noted palatal swelling about 20 years previously. Pathologically, the lesion was composed of two distinct tumors, pleomorphic adenoma and lumenless trabecular adenoma, which were sharply demarcated from each other by a thin layer of fibrous connective tissue. Foci of tumor cells with cellular atypia were seen in some areas of the pleomorphic adenoma. The present case is thought to represent a previously undescribed component within the spectrum of minor salivary gland tumors.     

Malignant melanoma of unknown primary site simulating a salivary gland neoplasm

Malignant melanoma with its varied clinical presentations and histomorphological patterns is a perplexing problem both for the diagnosticians and clinicians. A small proportion of melanomas present with metastatic tumors with unknown primary sites and at these sites they mimic the more common primary neoplasms. We hereby report a case of malignant melanoma presenting as a submandibular lump in a 40 year old female. This lump was present for six months and was rapidly increasing in size. On cytology it was diagnosed as salivary gland neoplasm.     

Epstein-Barr virus infected lymphoepithelial carcinomas of the salivary gland in the Russia-Asia area: a clinicopathologic study of 160 cases

In order to determine the prevalence of the Epstein-Barr virus (EBV) infection in salivary gland lymphoepithelial carcinomas (LEC), we have collected 160 cases from Asian countries and Russia. All the cases examined by PCR for EBV DNA BamHI fragment and in-situ hybridization for EBER-1, EBV encoded small RNA, showed positivity for EBV infection in LEC cells, while no positive signals were found in any other salivary neoplasm examined. The incidence of LEC was highest in Guanzhou, followed by Shanghai and Chengdu and lowest in the northern parts of China, Seoul, Niigata, and Moscow. The mean age of the patients with LEC was 43.9 years with no sex predilection. The Chinese patients were of the Han race, only including minor races. There were ninety-five cases found with LEC in the parotid gland (75%), 20 in the submandibular gland (5%), and 28 in the minor salivary gland (20%). Histologically, the LECs were classified into two types: small nest type and large nest type. The latter type consisted of large-sized tumor cell nests and dense lymphocytic stromata and more frequently occurred in the minor salivary gland. The former consisted of small-sized tumor cell nests with fibrous and lymphocyte-depleted stromata, which were more frequently found in the parotid gland. The results indicated that EBV infection and certain geographic factors play important roles in the pathogenesis of the salivary LEC.     

涎腺淋巴上皮癌的影像学与病理学特点分析

目的：探讨涎腺淋巴上皮癌(lymphoepithelial carcinoma,LEC)的CT、MRI及病理学特点。方法：回顾性分析22例涎腺LEC患者的影像学资料及病理组织学表现,其中18例行CT平扫及增强扫描,4例行MRI平扫及增强扫描。结果：22例患者中共检出22个病灶,位于腮腺16例,颌下腺6例。边界清楚6例,边界不清16例。CT上密度均匀16例,不均匀2例,MRI上信号均匀4例,T1WI上为低信号, T2WI上呈稍高信号,增强扫描中度强化12例,明显强化10例。8例侵犯周围结构,10例颌下及颈动脉鞘区见肿大淋巴结。组织学均表现为肿瘤性上皮细胞伴淋巴细胞间质浸润及免疫组织化学CK阳性表达。结论：涎腺LEC的影像学表现具有一定的特征性,肿块常密度或信号均匀,增强扫描中度至明显强化,坏死较少见,多伴有同侧颈部淋巴结肿大。病理学上改变符合组织学特点和免疫组织化学检测,结合影像学CT、MRI的定位,排除鼻咽癌转移,即可诊断为原发性涎腺LEC。     

Vascular endothelial cell participation in formation of lymphoepithelial lesions (epi-myoepithelial islands) in lymphoepithelial sialadenitis (benign lymphoepithelial lesion)

Lymphoepithelial lesions (LELs, or epi-myoepithelial islands) in lymphoepithelial sialadenitis (LESA, or benign lymphoepithelial lesion) of the salivary gland are known to be mainly composed of duct epithelial cells. However, other constituent cells are poorly characterized. Formalin-fixed paraffin sections obtained from six surgical specimens of LESA were examined using immunohistochemistry for cytoskeletal proteins, inflammatory cells, vascular endothelial cells, and extracellular matrix (ECM) molecules as well as by in situ hybridization for ECM molecules. In addition to keratin-immunopositive (+) duct-like epithelial cells, there were CD31/CD34+ vascular endothelial cells-which were either scattered in a singular fashion, in formed sheets, or in tubular structures-, CD20+ B lymphocytes, CD45RO+ T lymphocytes, and CD68 macrophages in the LELs. ECM molecules, such as heparan sulfate proteoglycan and tenascin, were immunolocalized in hyaline materials in the LELs. Their mRNAs were demonstrated mainly in endothelial cells and, to a lesser extent, in lympho-monocytic cells around hyaline materials, but were not as evident in epithelial constituent cells of LELs. The results indicate that endothelial cells as well as inflammatory cells are important constituents of the LELs, and the hyaline ECM cores mainly result from the intra-LEL angiogenesis by endothelial cells with the assistance of inflammatory cells. This intra-LEL vasculature seems to support regeneration and proliferation of salivary epithelial remnant cells.     

涎腺恶性多形性腺瘤161例临床病理分析

目的分析涎腺恶性多形性腺瘤（malignant pleomorphic adenoma,MPA）的临床病理特征。方法对经病理复片诊断为MPA的161例临床病理材料进行回顾性分析。结果161例MPA中,152例为原发性肿瘤、7例为局部复发性肿瘤、2例为肿瘤颈淋巴结转移灶。152例原发MPA中发生于腮腺85例、腭部39例、颌下腺21例、颊部3例、唇部2例、磨牙后区1例、上颌骨1例;男性95例,女性57例,男女比为1．7：1;发病年龄为27～92岁,平均59岁。恶性成分的组织学类型包括肌上皮癌62例、非特异性腺癌59例、腺样囊性癌8例、黏液表皮样癌7例、导管癌3例、腺鳞癌3例、上皮-肌上皮癌3例、癌肉瘤3例、未分化癌2例、腺泡细胞癌1例、黏液腺癌1例。组织学高、中、低度恶性的分别为45、69、38例。同一肿瘤中恶性成分≤50％的为21例,〉50％的为131例。侵袭性、微侵袭性、非侵袭性癌分别为106、10、33例。侵袭性癌、组织学分级与肿瘤发生颈淋巴结转移之间有显著相关性（P值均〈0．01）。结论MPA多见于中老年男性,好发于腮腺;临床表现多为无痛渐大性肿块,以近期生长迅速为特征;组织学表现为常同时具有良性多形性腺瘤成分和恶性肿瘤成分,侵袭性癌多见,恶性成分常多于良性成分,恶性成分以肌上皮癌和非特异性腺癌为多见;侵袭性癌、组织学分级高度恶性者易发生颈淋巴结转移。