Myoepithelial cell markers in salivary gland neoplasms

CCL28: A Promising Biomarker for Assessing Salivary Gland Functionality and Maintaining Healthy Oral Environments

The oral cavity serves as the primary path through which substances from the outside world enter our body. Therefore, it functions as a critical component of host defense. Saliva is essential for maintaining a stable oral environment by catching harmful agents, including pathogens, allergens, and chemicals, in the air or food. CCL28, highly expressed in mucosal tissues, such as the colon and salivary glands, is a chemokine that attracts CCR10/CCR3 expressing cells. However, the role of CCL28 in salivary gland formation remains unclear. In this study, we investigated the salivary gland structure in CCL28-deficient mice. Histological analysis showed decreased staining intensity of Alcian blue, which detects acidic mucous, reduced expression of MUC2, and higher infiltration of gram-positive bacteria in the salivary glands of CCL28-deficient mice. In addition, CCL28-deficient mice contained ectopically MUC2-expressed cells in the ducts and reduced the expression of cytokeratin 18, a marker for ductal cells, within the submandibular glands, resulting in decreased duct numbers. Additionally, the submandibular glands of CCL28-deficient mice showed reduced expression of several stem cell markers. These results suggest that CCL28 regulates saliva production via proper differentiation of salivary gland stem cells and could be a valuable biomarker of salivary gland function.

"Pleomorphic adenoma in salivary glands: Insights from a 100-patient analysis"

Introduction

Pleomorphic adenoma (PA) is a benign epithelial tumour originating from the salivary gland, specifically the parotid gland. This study aims to comprehensively analyse the clinical and pathological features of PA by examining the characteristics of the tumour, including its histological structure and immunohistochemical profile.

Materials and Methods

Over 8 years, beginning in October 2015 and ending in October 2023, an exhaustive retrospective study was conducted in the Department of Pathology, Kasturba Medical College, Mangalore, Manipal University, Karnataka, India. The research focused on 100 cases of pleomorphic adenoma and involved a meticulous examination of the clinical and pathological characteristics obtained by retrieving the pertinent files.

Results

Out of all the primary tumours, the majority (n = 70) was found in the parotid gland, followed by PA that developed from the minor salivary glands of the palate (n = 07), the submandibular gland (n = 17), and the lacrimal gland (n = 04). Only two cases had a primary tumour located in the lips. Females were more susceptible to these tumours than males. The parotid gland tumours showed a distinct trend in laterality, with 73 cases observed on the right side. In 85%, the initial symptom of the condition was painless swelling.

Conclusion

Salivary gland PA is typically a benign tumour. However, a subset of these tumours can exhibit a malignant phenotype. The preferred treatment is surgical excision with adequate margins.

Top Ten Differentials to Mull Over for Head and Neck Myoepithelial Neoplasms

BACKGROUND

Myoepithelial neoplasms of the salivary gland are benign or malignant neoplasms composed exclusively of neoplastic myoepithelial cells. These tumors, including the benign myoepithelioma and the malignant counterpart myoepithelial carcinoma, exhibit a wide range of cytomorphologic features and architectural patterns.

METHODS

Review.

RESULTS

Myoepithelial cells can be epithelial, plasmacytoid, clear cell, spindle cell, and/or oncocytic cell, arranging as trabeculae, solid sheets, nests, cords, and/or single cells. A stromal component is commonly but not universally present, Therefore, their differential diagnoses are quite broad, including salivary gland neoplasms especially those with a myoepithelial component, plasmacytoma, melanoma, and various mesenchymal tumors.

CONCLUSION

In this review, we summarize the characteristic histologic features, useful immunohistochemical panel, and common molecular alterations of myoepithelial tumors and their top differential diagnoses. A logical stepwise algorithmic approach and an immunohistochemical panel to include multiple myoepithelial markers are essential to establish the correct diagnosis.

Comparison of Diagnostic Reliability of p63 and Smooth Muscle Actin in Salivary Gland Neoplasms

Salivary gland neoplasms pose considerable diagnostic difficulty owing to their diverse histological features in individual lesions and the presence of a number of types and variants & similar histological features with other tumor entities. Myoepithelial and basal cells play a significant role in the pathogenesis of salivary gland neoplasm. p63 and smooth muscle actin are more reliable markers for identifying these cells and not studied much comparing their reliability in the diagnosis of salivary gland neoplasms. Hence, the aim of this study is to evaluate and compare the diagnostic reliability of immunohistochemical markers such as p63 and smooth muscle actin (SMA) in the diagnosis of various benign and malignant salivary gland neoplasms. The study comprises of 18 samples categorized into two groups: Group I comprised 9 cases, of which 4 cases were Pleomorphic adenoma, 2 cases were Myoepithelioma, 2 cases of Basal cell adenoma and 1 case was Warthin's tumor; and Group II consisted of 9cases, of which 3 was Mucoepidermoid carcinoma, 1 cases were Myoepithelial carcinoma and 5 cases were Adenoid cystic carcinoma. The selected cases were subjected to immunohistochemistry (IHC) procedure to assess the expression pattern of p63 and smooth muscle actin. The obtained data was analysed statistically by using Mann-Whitney test. In SMA, strong positivity for epithelial and connective tissue components of benign salivary neoplasm is about 22.2%respectively. In malignant salivary neoplasm, SMA was strongly positive for the epithelial and connective tissue component of about 77.7% and 88.8% cases respectively. The difference in the connective tissue components was found to be statistically significant (U = 24, P = 0.032). P63 was strongly positive for the epithelial and connective tissue component of benign salivary neoplasm of about 33.3% and 11.1% cases respectively.In malignant salivary neoplasm, p63 was strongly positive for the epithelial component of about 66.6% cases and connective tissue is completely negative. Alpha-SMA can be utilized as reliable IHC markers for salivary gland neoplasms due to its diagnostic importance in tumors with myoepithelial origin indicative of the histogenesis of salivary gland tumors and even p63 can be used as specific markers for differentiation of malignant salivary gland tumors.

Proliferative Activity of Myoepithelial Cells in of Mucoepidermoid Carcinoma

AIM: The aim of the study is to investigate the role of myoepithelial cells in the pathogenesis of mucoepidermoid carcinoma (MEC) using the double immunohistochemical staining; α _smooth muscle actin (_α-SMA)as specific marker for the myoepithelial cell differentiation and proliferative cell nuclear antigen (PCNA) as a marker for proliferative activity of myoepithelial cells. MATERIAL AND METHODS: Retrospective study of twenty salivary gland specimens (ten MEC and ten normal salivary glands) were studied using double immunohistochemical labeling for α _smooth muscle actin α-SMA) and proliferative cell nuclear antigen (PCNA). The SPSS statistical package was used for data analysis (IBM SPSS Statistics for Windows, Version 20.0, Released 2011, IBM Corp, and Armonk, NY, USA). RESULTS: In mucoepidermoid carcinomas, no positivity of α-SMA was seen in neoplastic cells (Frequent test), and it was just observed in the stroma of tumor, in the walls of blood vessels whereas, PCNA was positive, especially in high-grade tumors. In contrast, in normal salivary glands, the proliferating myoepithelial cells are stained by both α-SMA and PCNA. CONCLUSIONS: We believe that the myoepithelial cells have no a role in the development of mucoepidermoid carcinoma.

Plasmacytoid cells in salivary pleomorphic adenoma: an alternative interpretation of their immunohistochemical characteristics highlights function and capability for epithelial-mesenchymal transition

OBJECTIVES

Plasmacytoid cells (PLCs) in salivary pleomorphic adenoma (SPA) are regarded as modified neoplastic myoepithelia and define plasmacytoid myoepithelioma (pMYO). However, histochemically, immunohistochemically and ultrastructurally, PLCs fail to demonstrate frank myogenous properties. Epithelial-mesenchymal transition (EMT) may explain the phenotypes in SPA. Our aim was to evaluate (1) PLCs with accepted or purported myoepithelial and EMT-related markers; and (2) pMYOs for PLAG1 aberrations by using fluorescence in situ hybridization.

STUDY DESIGN

Eight SPAs with or without PLC-predominance and 3 pMYOs were immunohistochemically studied.

RESULTS

PLCs in SPA and pMYO exhibited strong, scattered to diffuse positivity for K7, rare K14 positivity and were mostly negative for α-smooth muscle actin, h-caldesmon, and p63/p40. S100 staining was strong and diffuse, whereas calponin was variable. DOG1 was negative. PLCs in pMYO and PLC-rich SPA exhibited selective or diffuse WT1 and D2-40 immunoreactivity. EMT markers SNAIL/SLUG exhibited strong and variable immunoreactivity in PLCs in contrast to weak or absent E-cadherin expression. SOX10 was diffusely and strongly positive. PLAG1 rearrangement was present in 1 pMYO.

CONCLUSIONS

PLCs mostly fail to express myoepithelial markers; PLCs are neoplastic cells adapting to microenvironmental changes and capable of EMT; and tumors composed solely of PLCs are apparently SPAs depleted of a ductal component.

Serial patient-derived orthotopic xenografting of adenoid cystic carcinomas recapitulates stable expression of phenotypic alterations and innervation

BACKGROUND

Patient-derived xenograft (PDX) models have significantly enhanced cancer research, and often serve as a robust model. However, enhanced growth rate and altered pathological phenotype with serial passages have repeatedly been shown in adenoid cystic carcinoma (ACC) PDX tumors, which is a major concern.

METHODS

We evaluated the fidelity of ACCs in their natural habitat by performing ACC orthotopic xenotransplantation (PDOX) in salivary glands.

FINDINGS

Our PDOX model enabled solid tumors to integrate within the local epithelial, stromal and neuronal environment. Over serial passages, PDOX tumors maintained their stereotypic MYB-NFIB translocation, and FGFR2 and ATM point mutations. Tumor growth rate and histopathology were retained, including ACCs hallmark presentations of cribriform, tubular, solid areas and innervation. We also demonstrate that the PDOX model retains its capacity as a tool for drug testing.

INTERPRETATION

Unlike the precedent PDX model, our data shows that the PDOX is a superior model for future cancer biology and therapy research. FUND: This work was supported by the National Institutes of Health (NIH)/National Institute of Dental and Craniofacial Research (NIDCR) grants DE022557, DE027034, and DE027551.

Utility of smooth muscle actin and CD117 as reliable markers in the diagnosis of salivary gland neoplasms

Objective:

The aim of this study is to analyze the utility of immunohistochemical markers such as CD117 and smooth muscle actin (SMA) in the diagnosis of various benign and malignant salivary gland neoplasms.

Materials and Methods:

The study comprises 17 samples categorized into three groups: Group I consisted of 5 histopathologically normal salivary gland tissue; Group II comprised 7 cases, of which 3 cases were pleomorphic adenoma, 3 cases were myoepithelioma and 1 case was Warthin's tumor; and Group III consisted of 5 cases, of which 1 was mucoepidermoid carcinoma and 4 cases were adenoid cystic carcinoma. The selected cases were subjected to immunohistochemistry (IHC) procedure to assess the expression pattern of CD117 and SMA.

Results:

In SMA, 85.8% showed severe-to-moderate intense expression among the tumor cells in benign salivary gland tumor. All the 5 malignant tumors showed the expression of SMA and 3 cases demonstrated severe expression among the tumor cells. An intense expression pattern of SMA was observed in both benign and malignant neoplasms in the periphery and stromal components of the tumor. Only two cases were positive for CD117, and connective tissue components were completely negative in both malignant and benign salivary gland neoplasms.

Conclusion:

Alpha-SMA can be utilized as reliable IHC markers for salivary gland neoplasms due to its diagnostic importance in tumors with myoepithelial origin indicative of the histogenesis of salivary gland tumors.

Clinicopathological effect of PLAG1 fusion genes in pleomorphic adenoma and carcinoma ex pleomorphic adenoma with special emphasis on histological features

AIMS

Pleomorphic adenoma gene 1 (PLAG1) rearrangement is well known in pleomorphic adenoma (PA), which is histologically characterised by admixed epithelial and mesenchymal components. Multiple fusion variants of PLAG1 and HMGA2 have been reported; currently, however, little is known regarding the clinicopathological impacts of these fusion types METHODS AND RESULTS: We examined the PLAG1- and HMGA2-related fusion status in 105 PAs and 11 cases of carcinoma ex PAs (CXPA) arising from salivary glands and lacrimal glands to elucidate their correlation to the clinicopathological factors. Forty cases harboured PLAG1 fusion genes: CTNNB1-PLAG1 in 22 cases, CHCHD7-PLAG1 in 14 cases and LIFR-PLAG1 in four cases. Only two cases possessed HMGA2 fusion genes. The mean age of LIFR-PLAG1-positive cases was significantly higher than that of CTNNB1-PLAG1- and CHCHD7-PLAG1-positive cases (P = 0.0358). PAs located in the submandibular gland demonstrated CTNNB1-PLAG1 fusion at a significantly higher rate than other fusions (P = 0.0109). Histologically, PLAG1 fusion-positive cases exhibited chondroid formation and plasmacytoid features more commonly (P = 0.043, P = 0.015, respectively) and myxoid abundant feature less frequently (P = 0.031) than PLAG1 fusion-negative cases. For CXPAs, four CTNNB1-PLAG1 fusions were detected in two salivary duct carcinomas and two myoepithelial carcinomas. Ductal formation was observed frequently (90.9%) in residual PA.

CONCLUSIONS

The presence of PLAG1 fusion was associated with specific histological features in PA. Detecting the PLAG1 fusion gene and searching residual ductal formation in salivary gland malignant tumours with extensive hyalinisation could be useful for diagnosis.

Comparison of p63/p40 Expression With Myoepithelial Markers in Minor Salivary Gland Tumors

The present study aimed to compare the expression of p63/p40 with smooth muscle actin (SMA) and vimentin (VIM) by myoepithelial cells in minor salivary gland tumors. Fifty-two formalin-fixed paraffin-embedded samples of minor salivary gland tumors derived from intercalated duct (pleomorphic adenoma [PA], adenoid cystic carcinoma [ACC], epithelial-myoepithelial carcinoma [EMC], polymorphous adenocarcinoma [PAC], and secretory carcinoma [SC]) and 3 samples of minor salivary gland tumors derived from excretory duct (mucoepidermoid carcinoma [MEC]) were evaluated by means of immunohistochemistry. The data were analyzed qualitatively. The results indicated that p63 and p40 expression were detected in myoepithelial cells present in PA, ACC, and EMC. However, both proteins were also observed in squamous areas of PA and all cases of MEC. SMA were noticed in some myoepithelial cells of PA, ACC, and EMC. Expression of SMA was negative in the other salivary gland tumors evaluated. VIM was constantly expressed by myoepithelial cells in PA, ACC, and EMC. VIM was also observed in cells of PAC and SC, but not in squamous areas of PA and MEC. In conclusion, p63 expression is almost comparable with VIM in detecting myoepithelial cells, an immunolabeling pattern not followed by p40, and consequently, caution has to be taken during the interpretation of salivary gland tumor exhibiting an p63/p40 phenotype in order to avoid a misdiagnosis.

Proliferative Activity of Myoepithelial Cells in Normal Salivary Glands and Adenoid Cystic Carcinomas Based on Double Immunohistochemical Labeling

Objective

To investigate the proliferative activity of myoepithelial cells (MEC) in normal salivary glands (NSG) and adenoid cystic carcinomas (ACC)) Study design. Twenty -three salivary gland specimens (13 ACC, 10 NSG) were studied using double immunohistochemical labeling for α smooth muscle actin (a-SMA) and proliferative cell nuclear antigen (PCNA)).

Results

There was a significant difference in PCNA reactivity in normal samples between myoepithelial cells of the parotid glands and of the submandibular glands, rates being higher in the latter. Neoplastic myoepithelial cells exhibited higher expression than neoplastic epithelial cells. In addition, myoepithelial cells of the cribriform type of ACC showed PCNA reactivity lower than those of the tubular type, whereas there was no statistically significant difference in epithelial cell rates. We could not identify myoepithelial cells in solid pattern due to α-SMA negativity; although high PCNA reactivity was evident.

Conclusion

These data suggest that the myoepithelial cell has a key role in ACC oncogenesis, more so than its epithelial cell counterparts. Moreover, the data provide a histopathological interpretation for aggressive clinical features of submandibular ACC, as the myoepithelial cells were less differentiated as compared to those of parotid glands.

Characterisation of DOG-1 Expression in Salivary Gland Tumours and Comparison with Myoepithelial Markers

DOG1 is an established diagnostic marker for gastrointestinal stromal tumours (GIST), but has been reported in salivary gland tumours (SGT) as an acinar and intercalated duct marker. However, its specificity and distribution is not well established. The aim of this study was to evaluate the diagnostic utility of DOG-1 expression in SGT in addition to comparing it with myoepithelial markers. Normal salivary tissue and SGT (n = 184) were examined for expression of DOG1 and a range of myoepithelial markers. SGT included: acinic cell carcinoma (ACC, n = 15), secretory carcinoma (SC, n = 9), pleomorphic adenoma (PA, n = 49), carcinoma ex-PA (Ca ex-PA, n = 11), adenoid cystic carcinoma (AdCC, n = 20), polymorphous adenocarcinoma (PAC, n = 6), myoepithelioma (n = 6), myoepithelial carcinoma (MC, n = 2), basal cell adenoma (BCA, n = 14), canalicular adenoma (CA, n = 19), mucoepidermoid carcinoma (MEC, n = 11), oncocytoma (n = 2), adenocarcinoma NOS (AdNOS, n = 4), basal cell adenocarcinoma (BCAC, n = 2), salivary duct carcinoma (SDC, n = 3) and papillary cystadenocarcinoma (PCAC, n = 1). Normal acini and ACC (14/15) showed strong luminal DOG1 staining; SC were largely negative with only focal expression in 3/9 cases. Luminal staining was seen in PA (14/49), PAC (4/6), Ca ex-PA (4/11) and AdCC (6/20). 8/11 MEC showed luminal and/or mucous cell staining. No staining was seen in myoepithelioma, MC, CA, adNOS and BCAC. BCA showed strong staining of myoepithelial cells in some cases (5/14). Variable myoepithelial DOG1 staining was seen in PA, Ca ex PA, BCA, SDC and PCAC which was not as consistent as myoepithelial markers such as calponin, p63 and αSMA. Absence of DOG1 can differentiate ACC from SC, but staining is variable in PA, PLGA and Ca ex-PA. Myoepithelial staining in some tumours but not in normal gland suggests a wider distribution in SGT than originally envisaged.

Palatal Polymorphous Adenocarcinoma with High-Grade Transformation: A Case Report and Literature Review

Polymorphous adenocarcinoma (PAC) is the second most common intraoral malignant neoplasm of the minor salivary glands. However, it is very rare for PAC to show high-grade transformation (HGT) and to our knowledge, the English literature only seven reported cases. HGT tends to be observed when PAC recurs, and it is extremely rare to be seen at initial presentation. Here we report a 43-year-old Japanese male patient with PAC of the right palate showing HGT at initial presentation. Histopathologically, the tumor was characterized by a prominent solid and papillary-cystic growth pattern, with nuclear atypia and necrosis in area of HGT. The immunohistochemical staining pattern was consistent with PAC, as the tumor cells showed diffuse positivity for cytokeratin, vimentin and S-100, and focal positivity for bcl-2, ɑ-SMA and EMA. The tumor cells in HGT areas were markedly positive for AR and Ki-67 (about 40%/HPF), and also focally positive for cyclin D1 and p53, whereas HER2/neu, ER, PgR, p63, D2-40, GCDFP-15, and mitochondria were negative. Here we present a very rare case of palatal PAC with HGT at initial presentation.

The value of fine needle aspiration cytology in the clinical management of rare salivary gland tumors

Salivary gland tumors are relatively rare neoplasms, mostly located in the parotid gland, and few are malignant. Preoperative evaluation of salivary gland tumors includes fine needle aspiration cytology (FNAC).

Mucoepidermoid carcinoma of the sublingual gland harboring a translocation of the MAML2 gene: A case report

Among tumors of the major salivary glands, tumors in the sublingual gland are rare. Although mucoepidermoid carcinoma (MEC) represents a histological type of salivary gland tumor, it is occasionally difficult to diagnose due to its histological variation. The present study reports a case of MEC harboring a mastermind-like transcriptional coactivator 2 (MAML2) gene translocation in the sublingual gland. A 76-year-old Japanese woman with a mass in the left submandibular region was referred to Kurume University Hospital (Kurume, Japan). Computed tomography scans revealed that the tumor was predominantly located in the sublingual gland, and tumor resection was performed. Histologically, the tumor was composed of cells that exhibited low-grade nuclear atypia and clear and/or granular eosinophilic cytoplasm, and that were proliferating in solid patterns. Periodic acid-Schiff and alcian blue staining revealed a small number of mucinous cells in the tumor. Immunohistochemically, the tumor cells were positive for p40 and p63. Fluorescence in situ hybridization (FISH) analysis revealed a MAML2 gene split. The definitive pathological diagnosis was low-grade MEC, as the case lacked any factors indicative of high-grade malignancy. To the best of our knowledge, this is the first report of MEC in the sublingual gland with MAML2 gene translocation confirmed by FISH.

Pleomorphic adenoma and adenoid cystic carcinoma of salivary glands: E-cadherin immunoexpression and analysis of the CDH1 -160C/A polymorphism

OBJECTIVE

Despite their similar cellular origin, pleomorphic adenomas (PA) and adenoid cystic carcinomas (ACC) present distinct behaviors. This study aimed to analyze the immunoexpression of E-cadherin in PA and ACC of salivary glands, and to investigate differences in its expression in relation to E-cadherin gene (CDH1) -160C/A polymorphism.

DESIGN

Twenty-four PA (15 cell-rich and 9 cell-poor tumors) and 24 ACC (10 tubular, 8 cribriform and 6 solid tumors) were selected for the analysis of pattern of distribution, and cellular localization of E-cadherin. In addition, E-cadherin expression was evaluated using the H-score scoring system. The CDH1 -160C/A polymorphism was investigated by PCR-RFLP.

RESULTS

No significant differences in pattern of distribution (p=0.181) and cellular localization (p=0.192) of E-cadherin were observed between PA and ACC. Comparison of PA and ACC cases revealed a higher median H-score in the latter (p=0.036). Cell-rich PA presented a higher H-score than cell-poor tumors (p=0.013), whereas no significant differences in E-cadherin expression were observed between ACC subtypes (p=0.254). The heterozygous genotype of the CDH1 -160C/A polymorphism was detected in only one PA and one ACC. H-scores for tumors carrying the polymorphism were below the lower quartile of their respective groups.

CONCLUSIONS

The results suggest that E-cadherin expression in PA and ACC is mainly related to cellular composition (epithelial cells versus myoepithelial cells) and degree of differentiation of myoepithelial cells in these tumors. The CDH1 -160C/A polymorphism does not seem to significantly influence the expression of E-cadherin in PA and ACC of salivary glands.

Biomarker Analysis in Carcinoma ex Pleomorphic Adenoma at an Early Phase of Carcinomatous Transformation

Diagnostic criteria for intracapsular carcinoma ex pleomorphic adenoma (CXPA) are subjective and vary among authors. Biomarker analysis, which could provide more objective evaluation of these tumors, has rarely been studied in intracapsular CXPA. Immunohistochemical evaluation of c-erbB-2, p53 protein, bcl-2, and Ki-67 was performed in 8 cases of CXPA at an early phase of malignant transformation (4 intracapsular and 4 minimally invasive) and in 17 pleomorphic adenomas (PA). In all cases of CXPA, p53 and Ki-67 were demonstrated predominantly in luminal cells of benign and malignant areas, significantly more in the latter. Few benign myoepithelial cells were p53 positive. c-erbB-2 reactivity was strongly associated with atypical luminal cells. Bcl-2 expression was weak and focal in malignant areas from 2 cases. In conclusion, both p53 and c-erbB-2 proteins appear to be involved at an early stage of malignization of PA. In PA with atypical cells, evaluation of the expression of these 2 markers provides more objective criteria for the diagnosis of intracapsular CXPA.

Cytology of the Salivary Glands

Common usage of fine-needle aspirate (FNA) for salivary gland lesions is the preoperative determination of whether a lesion is neoplastic, its lineage, and if neoplastic, whether it is low grade/benign, or high grade. Immunohistochemical stains can be performed on cell blocks to determine lineage and help refine diagnosis, although their performance is not always equivalent to that seen in surgical specimens. Several characteristic translocations have been described in various entities in these categories, and these can be evaluated using fluorescence in situ hybridization. In the future, high-throughput next-generation sequencing panels may further refine cytologic diagnosis in salivary tumors.

Establishment and characterization of a cell line from human adenoid cystic carcinoma of the lacrimal glands and a nude mouse transplantable model

Using tissue block culture techniques, we established a new human tumor cell line derived from adenoid cystic carcinoma of the lacrimal glands (LACC-1). The LACC-1 cell line was successfully subcultured for more than 100 passages during the last two years. The outgrowth of cells was observed by day 5 after seeding, and then the cells were generated slowly. The first passage proceeded by day 32, and the classical epithelioid cell colonies formed by day 69 after inoculation. After eight passages, homogeneous epithelioid tumor cells appeared when we combined continuous passage, mechanical scraping, repeated adherence, and dissociation methods to remove the fibroblast cells. LACC-1 cells appeared as a histologically solid pattern and continuous passage culture. The population doubling time was approximately 37.1 h. LACC-1 cells appeared as an epithelioid monolayer culture on the cell culture flask and presented with a cobblestone-like appearance when they reached confluency. The nucleus was large and round with many abnormal mitoses. The nucleoplasm ratio was high. Multinucleated tumor giant cells appeared. LACC-1 cells showed a tendency to have overlapping growth without contact inhibition when the cell density continued to increase. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the LACC-1 cells were malignant tumor cells that were poorly differentiated. The surface of the LACC-1 cells exhibited affluent microvilli, protuberances and filopodia under SEM. The no. 84 generation LACC-1 cell line was inoculated subcutaneously into the subaxillary of nude mice and the tumorigenic potential was evident. The formation rate of the transplanted tumors was 100% at day 7 after inoculation. This finding showed that the LACC-1 cell line was malignant with tumorigenic ability. The xenograft tumors retained the same histological characteristics of a solid pattern as the LACC-1 original tumor after inoculation for 49 days. Under TEM observation, the xenograft tumor cells had the same ultrastructure as the LACC-1 cells. Immunohistochemical examination revealed the similarity of both cytoskeletal proteins (e.g., cytokeratin, vimentin, desmin and α-SMA) and S-100 expression in the original tumor, LACC-1 cells and xenograft tumors. Immunoreactivity of these proteins was gradually decreased in these three tissues. Reverse transcription-polymerase chain reaction demonstrated that the xenograft tumors originated from the human. Based on these results, the LACC-1 cell line provides a useful model for studying the biological characteristics of human ACC of the lacrimal glands.

Myoepithelial Cells (MEC) of the Salivary Glands in Health and Tumours

Myoepithelial cells (MEC) are found in the secretory units of many mammalian exocrine glands such as mammary, sweat, lacrimal and salivary glands. They are interposed between the secretory cells and the basal lamina. Immunohistochemically they are found to contain keratin intermediate filaments and are, therefore, considered to have an epithelial origin but at the same time they contain a large number of myofilaments which represent a massive expression of contractile proteins such as actin, myosin, calponin and caldesmon. Thus have smooth muscle like property also and hence the name. Numerous functions of MEC have been described, the most important of them being important for contraction of the glands and recently it has been found to prevent tumour progression. It should be noted that the diversity in the occurrence and dilemma regarding the pathogenesis of salivary gland tumours is due to lack in uniformity regarding the cells participating in its oncogenesis, especially the MEC. Also proper and extensive studies regarding MEC are very limited and thus have posed difficulty for a pathologist to understand this cell. In this review we try to bring about a thorough description of this cell in both physiological and pathological aspects.

Polymorphous low-grade adenocarcinoma of the upper lip with metachronous myoepithelioma of the buccal mucosa

Examples of multiple minor salivary gland tumors, synchronous or metachronous, are uncommon. We report a patient who initially presented with polymorphous low-grade adenocarcinoma (PLGA) and subsequently with myoepithelioma. A 91-year-old white woman presented in 2009 with a 1-cm, firm, nontender, well-circumscribed nodule of the left side of the upper lip extending to the anterior buccal mucosa. Excisional biopsy revealed PLGA. While the margins were positive, further treatment was not recommended due to the patient's age. In 2011, the patient returned with a 1.5-cm, asymptomatic mass of the left buccal vestibule. Excision of the lesion revealed a circumscribed proliferation of epithelioid and plasmacytoid cells arranged in spherical or whorl-like islands and immersed in a mucinous stroma, consistent with myoepithelioma. The PLGA recurred 3 years after initial diagnosis. Excision was again associated with positive margins, and again no further treatment was recommended. A few months later, at a scheduled follow-up appointment, she presented with a painless nodule of the left upper lip, consistent with recurrent PLGA. One month later, the patient died of unrelated causes. We also present a literature review of multiple minor salivary gland tumors.

A spontaneous epithelial-myoepithelial carcinoma of the submandibular gland in a sprague-dawley rat

The present report describes a rare case of spontaneous tumor of the salivary gland in a male Sprague-Dawley rat. The clinically confirmed mass rapidly developed in the cervical region between 19 and 21 weeks of age, and the animal was subsequently euthanized. At necropsy, a well-circumscribed nodule approximately 7 × 6 cm in diameter was found at the site of the salivary gland. The cut surface of the nodule was lobulated and soft and had a pinkish tan fish-flesh appearance. One large cyst (approximately 3 × 2 cm in size) containing reddish fluid was also present in the nodule. Histopathologically, the tumor, with a partially lobulated structure, was surrounded by a thin fibrous capsule. The majority of tumor cells formed a diffuse solid sheet structure that mainly consisted of small ovoid or spindle-shaped cells. In the tumor periphery, some cells were arranged in nest-like structures. Small duct-like structures lined with a monolayer of cuboidal epithelial cells resembling an intercalated duct or large polygonal clear cells with a myoepithelial component were also observed. Mitotic figures and necrotic foci were frequently observed in solid areas. Immunohistochemically, the tumor cells were positive for cytokeratin, epithelial membrane antigen, vimentin, p63, α-smooth muscle actin and calponin. The cells were negative for calcitonin, synaptophysin and chromogranin A. On the basis of these findings, the tumor was diagnosed as an epithelial-myoepithelial carcinoma originating from the luminal epithelial cells and myoepithelial cells in the submandibular gland.

Takahashi R, Nagai T, Yoshida M, Suzuki F, Obikane H, Yamashina M, Matsubayashi J. Immunohistochemical analysis of salivary gland tumors: application for surgical pathology practice

Salivary gland tumors are relatively uncommon and there exists a considerable diagnostic difficulty owing to their diverse histological features in individual lesions and the presence of a number of types and variants, in addition to overlapping histological patterns similar to those observed in different tumor entities. The classification is complex, but is closely relevant to the prognostic and therapeutic aspects. Although hematoxylin-eosin staining is still the gold standard method used for the diagnosis, immunohistochemistry (IHC) can enhance the accuracy and be a helpful tool when in cases to investigate the subjects that cannot be assessed by histological examination, such as the cell nature and differentiation status, cell proliferation, and tumor protein expression. This review depicts on the practical diagnostic utility of IHC in salivary gland tumor pathology under the following issues: assessment of cell differentiation, focusing on neoplastic myoepithelial cells; discrimination of histologically mimic tumor groups; diagnosis of specific tumor types, e.g., pleomorphic adenoma, adenoid cystic carcinoma, and salivary duct carcinoma; and evaluation of malignancy and prognostic factors. IHC plays a limited, even though important, role in the diagnosis of salivary gland tumors, but is often useful to support the histological assessment. However, unfortunately few tumor type-specific markers are still currently available. For these reasons, IHC should be considered a method that can be used to assist the final diagnosis, and its results themselves do not directly indicate a definitive diagnosis.

Pleomorphic adenoma with extensive squamous metaplasia and keratin cyst formations in minor salivary gland: a case report

Pleomorphic adenoma (PA), the most common salivary gland tumor, accounts for 54 to 65% of all salivary gland neoplasias and 80% of the benign salivary gland tumors. It most frequently affects the parotid gland, followed by the submandibular and the minor salivary glands. Microscopically, mucous, sebaceous, oncocytic and squamous metaplasia, sometimes with the formation of keratin pearls, may be present, but the latter rarely results in the formation of extensive keratin-filled cysts lined by squamous epithelium. Extensive squamous metaplasia can be mistaken for malignancy, including mucoepidermoid carcinoma and squamous cell carcinoma. Here, we present an unusual case of PA with extensive squamous metaplasia and keratin cyst formations in a minor salivary gland, and discuss its microscopic features, including the immunohistochemical characteristics, and differential diagnosis of this uncommon presentation.

WT1 expression in salivary gland pleomorphic adenomas: a reliable marker of the neoplastic myoepithelium

Pleomorphic adenoma is a benign salivary gland neoplasm with a diverse morphology. This is considered to be a function of the neoplastic myoepithelium, which shows histological and immunophenotypical variability. Wilms' tumor 1 gene (WT1) protein, involved in bidirectional mesenchymal-epithelial transition, has been detected by reverse transcription PCR in salivary gland tumors showing myoepithelial-epithelial differentiation. The aim of this study was to investigate the immunoreactivity of WT1 in pleomorphic adenomas and to compare the pattern of staining with p63 and calponin, two reliable markers of myoepithelial cells. A total of 31 cases of pleomorphic adenoma were selected. The myoepithelium was classified as myoepithelial-like (juxtatubular and spindled), modified myoepithelium (myxoid, chondroid and plasmacytoid) and transformed myoepithelium (solid epithelioid, squamous and basaloid cribriform). Immunohistochemistry for WT1, p63 and calponin was assessed in each myoepithelial component, as well as in nonneoplastic myoepithelial cells and inner tubular epithelial cells. There was no immunostaining of tubular epithelial cells by any of the markers. In contrast to p63 and calponin, WT1 did not react with normal myoepithelial cells. Cytoplasmic WT1 staining was present in all pleomorphic adenomas, and in 29 cases (94%), >50% of neoplastic myoepithelial cells were highlighted. p63 and calponin stained the myoepithelium in 30 tumors. In comparison, 50% of cells were positive in 21 (68%) and 9 (29%) cases of p63 and calponin, respectively. Staining with WT1 showed less variability across the spectrum of myoepithelial differentiation with the difference most marked in the transformed myoepithelium. WT1 is a sensitive marker of the neoplastic myoepithelial cell in pleomorphic adenomas. The role of this protein in influencing the mesenchymal-epithelial state of cells suggests that WT1 and the myoepithelial cell have an important role in the histogenesis of pleomorphic adenomas.

Spontaneous Basal cell carcinoma of the submandibular gland in a rat

At necropsy, a white nodule (about 5 × 3 mm in size) was observed in the right submandibular gland of a 10-week-old female GALAS rat. Histopathologically, oval to spindle-shaped and pale basophilic tumor cells proliferated closely, and formed variably sized foci. The nodule partially spread into or invaded the surrounding normal tissue, and necrotic foci were recognized in the tumor. Immunohistochemically, the nuclei of the tumor cells showed a diffusely positive reaction for p63, and the cytoplasm showed a diffusely positive reaction for cytokeratin and negative reaction for αSMA, vimentin, desmin and S-100. Many tumor cells were positive for PCNA. Ultrastructurally, the tumor cells contained many tonofilaments in the cytoplasm and a few desmosomes at the intercellular portion. Based on these findings, the tumor was diagnosed as a basal cell carcinoma originating from the duct in the rat submandibular gland.

The cell with a thousand faces: detection of myoepithelial cells and their contributions in the cytological diagnosis of salivary gland tumors

Myoepithelial cells are an important component of salivary gland tumors and are partly responsible from the diverse histology of them. In this study, we focus on the myoepithelial cell differentiation by using cytological morphology in a various types of salivary gland tumors especially with regard to their contribution to the diagnosis. The relation of myoepithelial cells with stromal matrix and the associated epithelial cells were evaluated. Cytologic slides of one hundred and forty one benign and twenty malignant salivary gland tumors were examined for identification of morphologically different myoepithelial cells such as; spindle-stellate, polygonal-epitheloid, plasmacytoid, basal and clear types. The best examples of myoepithelial cells were detected in pleomorphic adenomas, in some monomorphic adenomas and in the adenoid cystic carcinoma cases. Most of the pleomorphic adenomas were composed more than one type of myoepithelial cells and epitheloid-spindle cell combination was frequent. Basal and clear cell types of myoepithelial cells closely resembled the epithelial cells and their identification was relatively difficult. Identification of myoepithelial cell types was easier when they were associated with stromal matrix material and stood as a secondary layer around tubule-forming epithelial cells. Myoepithelial cell components of various salivary gland tumors may be quite different and identification of myoepithelial cell types may pose difficulties. A confident cytologic identification of myoepithelial cells may be critical part of diagnosing salivary gland tumors.

Pleomorphic adenoma (benign mixed tumour) of the minor salivary glands of the upper lip

Pleomorphic adenoma is the benign tumor of salivary glands, which originates from the myoepithelial cells and intercalated duct cells. This tumor is more common in major salivary glands. This case report describes a rare and unusual lesion in a 55-year-old female, which was diagnosed as pleomorphic adenoma of the minor salivary glands in the upper lip. The tumor was a circumscribed, submucosal nodule, about 2.0 cm in diameter and was characterized by slow growth and rubbery consistency. Complete excision was performed and the histopathological analysis showed an epithelial salivary gland tumor with islands of plasmacytoid cells, duct like structures, in a variable stroma with chondroid, fibrous and myxoid appearance. No recurrence was observed 1 year after the surgery.

Myoepithelial carcinoma of the parotid gland with bilateral thyroid involvement: A case report and review of the literature

A patient was admitted to hospital with enlarged lobes of the thyroid gland with bilateral cervical lymph node involvement, and surgical excision followed. Histological examination of this specimen revealed a lesion that showed myoepithelial cell differentiation. Primary thyroid and skin appendage tumors were excluded based on clinical examination, conventional histology and immunohistochemistry. A tumor of the right parotid surgically treated in June 2008, approximately 2 years previously, was originally classified as a basal cell adenocarcinoma with focal invasion, but was re-examined. Using immunohistochemistry, the parotid tumor was re-classified as a myoepithelial carcinoma. The thyroid tumor proved to be metastasis from a primary parotid tumor, which was not found in the updated review of the literature. The literature is reviewed, including current knowledge on the histological and immunohistochemical features of myoepithelial carcinoma, with limited data on treatment suggestions.

Salivary Gland Myoepithelioma with Focal Capsular Invasion

Salivary gland tumors that display myoepithelial differentiation exclusively or predominantly are relatively uncommon, and the assessment of malignancy in a myoepithelial tumor can be difficult. We report a case of parotid gland myoepithelioma composed predominantly of spindle cells with focal capsular invasion. The patient was a 65-year-old woman who presented with a painless mass in the right preauricular region. Histologically, the tumor had a solid and multinodular growth pattern and was predominantly made up of spindle cells with a minor component of epithelioid cells with moderate cellular atypia. Focal regions of tumor cells infiltrated the capsule with tongue-like processes, hut tumor infiltration into the adjacent parotid tissue was absent. The tumor cells showed strong cytoplasmic immunoexpression of vimentin, pankeratin, S-100 protein, and smooth-muscle actin. Immunostains with glial fibrillary acidic protein, melanoma marker, epithelial membrane antigen, and carcinoembryonic antigen were negative. Expression of p53 was observed focally in the nuclei of the tumor cells. A final diagnosis of salivary gland myoepithelioma with focal capsular invasion was made, and the case was regarded as a myoepithelial tumor of uncertain malignant potential. In this report, we discuss the histologic criteria required to diagnose malignancy in salivary gland myoepithelial tumors.

Angiogenesis in salivary carcinomas with and without myoepithelial differentiation

To investigate whether salivary carcinomas with and without myoepithelial differentiation could present differences regarding degree of angiogenesis, we compared tumor vascularization between adenoid cystic (31 cases) and epithelial-myoepithelial carcinomas (14) versus mucoepidermoid (37) carcinoma. The expression of peroxiredoxin I was also studied to verify the potential relationship between cellular metabolism and microvascular density. Microvascular density for CD34 and CD105 were significantly lower in carcinomas with myoepithelial differentiation. However, no correlation was found between degree of angiogenesis and amounts of myoepithelial cells. High-grade peroxiredoxin I expression was found in 73.7% of mucoepidermoid carcinomas, whereas 85.1% of carcinomas with myoepithelial differentiation presented low-grade expression. In conclusion, carcinomas with myoepithelial differentiation, regardless of the amounts of myoepithelial cells, are associated to a significantly lower vascular density. The reasons for this lower angiogenic activity remain to be determined but could be related to metabolic characteristics of the cancer cells.

Myoepithelial carcinoma of the submandibular gland: report of a case with multiple cutaneous metastases

Myoepithelial carcinoma is a rare and aggressive neoplasm of the salivary glands. One-third of the patients may develop regional distant metastases, and lungs and kidneys have been regarded as the most usual sites for implantation. There is, however, little information on the metastatic behavior of this malignancy. We report the first case of patient with multiple cutaneous metastases from a myoepithelial carcinoma of the submandibular gland, which depicted a very aggressive clinical course.

Ameloblastoma, calcifying epithelial odontogenic tumor, and glandular odontogenic cyst show a distinctive immunophenotype with some myoepithelial antigen expression

BACKGROUND

Odontogenic neoplasms have some morphologic overlap with salivary gland neoplasms, many of which show myoepithelial differentiation. In the 1980s, an ultrastructural study identified a population of myoepithelial-like cells in calcifying epithelial odontogenic tumor. Myoepithelial derived tumors have since been shown to have distinct immunohistochemical profiles.

METHODS

We examined a series of odontogenic neoplasms, including 11 ameloblastomas, four calcifying epithelial odontogenic tumors, five glandular odontogenic cysts (GOCs), and five keratocystic odontogenic tumors with a panel of myoepithelial-associated immunohistochemical stains. We also assessed representative control examples of oral mucosa, odontogenic rests, and dentigerous cysts.

RESULTS

All of the neoplastic and non-neoplastic oral epithelium-derived entities share a p63-positive, high molecular weight cytokeratin (CK5/6)-positive immunophenotype. Calponin reactivity was at least focally present in two of four calcifying epithelial odontogenic tumors, three of five GOCs, and 10 of 11 ameloblastomas; the sole completely non-reactive ameloblastoma represents a lung metastasis. One case of calcifying epithelial odontogenic tumor was focally positive for glial fibrillary acidic protein. However, other more definitive markers of myoepithelial differentiation, including S-100 and smooth muscle actin, were negative. Two of three calcifying epithelial odontogenic tumors and five of five GOCs were also positive for a low molecular weight cytokeratin (CK7).

CONCLUSIONS

Ameloblastomas, GOCs, and calcifying epithelial odontogenic tumors show a distinctive immunophenotype which overlaps with that of myoepithelial-derived salivary gland neoplasms but does not provide definitive support for myoepithelial differentiation.

Necrotizing sialometaplasia versus invasive carcinoma of the head and neck: the use of myoepithelial markers and keratin subtypes as an adjunct to diagnosis

AIMS

To investigate the use of immunohistochemistry in distinguishing necrotizing sialometaplasia (NSM) from squamous cell (SCC) and mucoepidermoid carcinoma (MEC) by (i) the identification of myoepithelial cells and (ii) cytokeratin (CK) expression.

METHODS AND RESULTS

Thirteen cases with the histological changes of NSM, eight SCCs and eight MECs were examined with the following immunohistochemical markers: calponin, S100, smooth muscle actin (SMA), p63, CK7, CK5, CK6 and CAM5.2. The distribution and intensity of staining were recorded. Residual myoepithelial cells (best demonstrated by calponin and SMA) were identified at the periphery of the epithelial islands in all cases of NSM (although not in all islands), in contrast to MEC and SCC. S100 showed a similar pattern, although staining fewer cells. Moderate rather than extensive expression of CK7 may help to distinguish NSM from MEC.

CONCLUSION

Identification of myoepithelial cells and CK7 expression may help to distinguish NSM from its mimics.

Structural components of the nonstriated contractile apparatuses in the Caenorhabditis elegans gonadal myoepithelial sheath and their essential roles for ovulation

Ovulation in the nematode Caenorhabditis elegans is regulated by complex signal transduction pathways and cell-cell interactions. Myoepithelial sheath cells of the proximal ovary are smooth muscle-like cells that provide contractile forces to push a mature oocyte into the spermatheca for fertilization. Although several genes that regulate sheath contraction have been characterized, basic components of the contractile apparatuses of the myoepithelial sheath have not been extensively studied. We identified major structural proteins of the contractile apparatuses of the myoepithelial sheath and characterized their nonstriated arrangement. Of interest, integrin and perlecan were found only at the dense bodies, whereas they localized to both dense bodies and M-lines in the striated body wall muscle. RNA interference of most of the myofibrillar components impaired ovulation in a soma-specific manner. Our results provide basic information that helps understanding the mechanism of sheath contraction during ovulation and establishing a new model to study morphogenesis of nonstriated muscle.

Basal/myoepithelial cells in chronic sinusitis, respiratory epithelial adenomatoid hamartoma, inverted papilloma, and intestinal-type and nonintestinal-type sinonasal adenocarcinoma: an immunohistochemical study

CONTEXT

The pathogenesis of respiratory epithelial adenomatoid hamartoma (REAH) and inverted papilloma (IP) is poorly understood, especially compared with sinonasal adenocarcinoma (SNAC). One feature of malignant glandular lesions is loss of the basal/myoepithelial layer. The immunophenotype of the basal/myoepithelial layer has not been fully examined in benign glandular lesions of the sinonasal tract.

OBJECTIVE

To examine benign and malignant glandular lesions in the sinonasal tract for the immunophenotype of basal/myoepithelial cells, proliferation index, and cytokeratin and intestinal differentiation profiles.

DESIGN

Sinonasal adenocarcinoma (intestinal-type adenocarcinoma [ITAC] and nonintestinal type adenocarcinoma [non-ITAC]), REAH, IP, and chronic sinusitis (CS) were stained for cytokeratin (CK) 7, CK20, 34betaE12, CDX-2, p63, Ki-67, smooth muscle actin (SMA), S100 protein, and calponin.

RESULTS

Basal/myoepithelial cells in CS and REAH were positive for p63 and 34betaE12 but negative for SMA, S100 protein, and calponin. Proliferative activity was localized to the compartment containing p63-positive cells. Inverted papilloma demonstrated broad areas staining for p63 and 34betaE12, with intermediate proliferative activity in these areas. Sinonasal adenocarcinoma had the highest Ki-67 labeling index, and p63-positive SNACs had higher proliferation indices than p63-negative SNACs. REAH, IP, CS, and most SNACs expressed CK7. Only SNAC expressed CK20. Sixty percent of morphologic ITACs expressed CDX-2.

CONCLUSIONS

Basal/myoepithelial cells in CS and REAH should be considered basal and not myoepithelial cells. In benign lesions, proliferative activity is limited to the compartments with p63 staining. In SNAC and IP, p63 expression correlates with proliferation index. REAH, IP, and CS share similar immunoprofiles (CK7+, CK20-, and CDX-2-), contrasting with SNAC (CK7+, CK20+/-, CDX-2-/+).

Epithelial-myoepithelial carcinoma: a review of the clinicopathologic spectrum and immunophenotypic characteristics in 61 tumors of the salivary glands and upper aerodigestive tract

To further define the clinicopathologic spectrum of epithelial-myoepithelial carcinoma (EMCa), we report the gross, histologic, and immunophenotypic characteristics of 61 tumors seen within a 30-year-period. The mean age at presentation was 60.9 years, with a female predominance (1.5:1). The most common sites were parotid (62.1%), sinonasal mucoserous glands (10.3%), palate (8.6%), and submandibular (8.6%). Most EMCas showed a characteristic nodular/multinodular growth pattern and classic biphasic tubular histology. However, new morphologies in EMCa such as ancient change (8.2%), "Verocay"-like change (3.3%), and sebaceous differentiation (13.1%) were noted. Specific histologic variants were dedifferentiated EMCa (3.3%), oncocytic EMCa (8.2%), EMCa ex pleomorphic adenoma (1.6%), double-clear EMCa (3.3%), and EMCa with myoepithelial anaplasia (3.3%). All cytokeratin cocktails selectively highlighted the epithelial component well. Of the myoepithelial markers, p63, smooth muscle actin and vimentin performed best. Bcl-2 and c-kit were frequently positive (66.7% and 69.2%, respectively). p53 was highly expressed only in 1 dedifferentiated EMCa. The recurrence rate was 36.3% (median disease-free survival 11.34 y), but death was rare with 5-year and 10-year disease-specific survivals of 93.5% and 81.8%, respectively. The most important univariate predictors of recurrence were margin status (log rank P=0.006), angiolymphatic invasion (P=0.002), tumor necrosis (P=0.004), and myoepithelial anaplasia (P=0.038). Thus, EMCa is generally a low-grade tumor with a broader morphologic spectrum than previously thought, with several key features predictive of recurrence. Immunohistochemistry can aid diagnosis by highlighting the biphasic nature of the tumor.

Basal cell adenocarcinoma of the oral minor salivary glands: review of the literature and presentation of two cases

Basal cell adenocarcinoma (BCA) is an unusual salivary gland malignancy that very rarely affects the minor glands. Here we present 2 cases of BCA arising in the minor salivary glands of the left cheek and junction of the hard and soft palate, respectively. The patients were both women aged 66 and 42 years. The tumors assumed a tubular-trabecular and a solid-membranous pattern, respectively. Both tumors showed immunopositivity for S-100, Bcl-2, and cytokeratin 7. One tumor was also immunopositive for epithelial membrane antigen and carcinoembryonic antigen, and the other tumor was reactive with p53 and vimentin. Both tumors were surgically removed. A comprehensive literature review revealed only 21 previously reported cases of BCA of oral minor salivary glands. This is an exceptionally rare salivary gland tumor, which, despite its low-grade behavior, demands complete surgical removal with adequate margins. Immunohistochemical studies may complement a thorough histopathologic analysis in discriminating BCA from other salivary gland tumors.

Immunohistochemical expression of vimentin, calponin and HHF-35 in salivary gland tumors

Myoepithelial cells present a complex immunophenotype, with the expression of proteins varying according to the stage of normal or neoplastic differentiation of the cell. In order to evaluate the immunohistochemical markers expressed by these cells, a panel of antibodies composed of vimentin, calponin and HHF-35 was applied to 28 salivary gland tumors. The results demonstrated a higher percent sensitivity of vimentin and calponin compared to HHF-35. However, calponin and HHF-35 presented a focal labeling pattern in contrast with the diffuse distribution of vimentin. The cells predominantly stained by all tested antibodies included nonluminal cells in duct-like and tubular structures, such as those seen in pleomorphic adenomas and adenoid cystic carcinomas, as well as cells in the cords and nests of polymorphous low-grade adenocarcinomas and peripheral cells of sheets and nests of myoepitheliomas. In conclusion, the combination of calponin and vimentin is suggested for the identification of myoepithelial cells in salivary gland tumors.

Beta-catenin and E-cadherin expression in salivary gland tumors

This study evaluated the expression of E-cadherin and beta-catenin in salivary gland tumors. Twelve biopsy specimens from cases diagnosed as pleomorphic adenoma, 17 adenoid cystic carcinomas, 10 epithelial-myoepithelial carcinomas, and 4 polymorphous low-grade adenocarcinomas were immunohistochemically labeled for E-cadherin and beta-catenin antibodies. Healthy salivary glands were used as controls. Membrane-associated E-cadherin and beta-catenin expression was present in all the tumor types studied. E-cadherin and beta-catenin showed a similar distribution; however, beta-catenin labeling was weaker than that for E-cadherin. In the epithelial-myoepithelial carcinomas, myoepithelial cells exhibited diffuse nuclear staining, although occasional cells presented only focal labeling. Epithelial-myoepithelial carcinomas present changes in [.beta]-catenin expression but the other salivary tumors studied do not, which may reflect divergence in tumorigenesis of this extensive subset of salivary gland tumors.

Metallothionein immunostaining in adenoid cystic carcinomas of the salivary glands

Metallothionein (MT) is a protein that has been studied in several tumors as a prognostic factor and as a potential myoepithelial cell marker in breast cancer. The aims of this study were to assess the immunohistochemical staining of MT in adenoid cystic carcinomas of the salivary glands (ACC), and to analyze possible morphological and quantitative variations among the solid, cribriform, and tubular histological subtypes. MT was investigated in 15 cases of ACC using the immunohistochemical technique. All of the cases expressed the MT antigen. This expression was noteworthy in cells depicting myoepithelial differentiation. ACC with predominant tubular pattern presented a significantly lower mean index of MT immunopositivity than did solid or cribriform subtypes, while these two latter groups did not differ in terms of MT expression. Our results suggest that MT may be an important tool for immunolocalization of myoepithelial tumor cells in salivary gland neoplasms.

Immunoreactivity for Sex Steroid Hormone Receptors in Pulmonary Hamartomas

Sex steroid hormone [ie, estrogen (ER), progesterone (PgR), and androgen (AR)] receptors have been identified previously in normal salivary glands and, more variably, in salivary gland and salivary gland-type tumors. No data are available, however, on their expression in pulmonary hamartoma, a benign biphasic tumor consisting of reactive epithelial cells and neoplastic fibromyxoid stroma, cartilage and fat, which shares some morphologic, immunophenotypic, and genotypic features to pleomorphic adenoma of major salivary glands. Thirty pulmonary hamartomas (15 in male patients and 15 in age-matched female patients), were evaluated for ER, PgR, and AR immunoreactivity, and also for mesenchymal, epithelial, and myoepithelial markers, in the fibromyxoid, epithelial, and chondroid components. ER immunoreactivity was encountered in 90% of hamartomas, PgRs in 90%, and ARs in 53% (P<0.001), but not in normal lung tissues. ARs were confined to males (P<0.001), with a marginal prevalence in the fibromyxoid component (P=0.067). PgRs and ERs were instead present in both sex, with the former being restricted to the fibromyxoid stromal component (P<0.001) and the latter preferentially located in epithelial cells (P=0.107). In most cases, fibromyxoid stroma and spindle cells surrounding the chondroid foci displayed simultaneous immunoreactivity for ERs, PgRs, and ARs, along with immunoreactivity for vimentin, S-100 protein, glial fibrillary acid protein, smooth muscle actin, and calponin but lack of staining for cytokeratins. This profile is consistent with an incomplete myoepithelial differentiation of the receptor-expressing mesenchymal cells. In conclusion, sex steroid hormone receptor expression is a nonrandom event in pulmonary hamartoma, and may be related to the development and growth of this tumor.

Immunoprofile of reactive salivary myoepithelial cells in intraductal areas of carcinoma ex-pleomorphic adenoma

The myoepithelial cell (MC) is a component of various secretory glands, including salivary glands. Besides its function, a tumor suppressor and a tumor facilitating functions have been attributed to this cell. We investigated the immunoprofile of benign MC in intraductal areas of carcinoma ex-pleomorphic adenoma (CXPA), comparing them with the MC in duct-like areas of pleomorphic adenoma, origin of the malignant tumor. Antibodies against myoepithelial markers-CK14, alpha-SMA, calponin, P63, CD10, and D2-40-plus laminin and maspin was applied in four selected cases of intracapsular and minimal invasive CXPA with only luminal differentiation presenting areas of intraductal carcinoma. The immunohistochemical reactions of all the antibodies showed stronger staining in benign MC surrounding the malignant epithelial cells than in benign MC in duct-like areas of pleomorphic adenoma, thus revealing that in the malignization process the benign MC become differentiated and produce important proteins related to the tumor suppressor function.

Application of Two Different Clones of Vimentin to the Diagnosis of Salivary Gland Tumors

With the evolution of IHC techniques, a broad range of antibodies have become available to diagnostic immunohistology. The authors observed different expressions of vimentin in salivary gland tumors using two clones of this antibody. This study was undertaken to show these differences comparing the immunoexpression of two clones of vimentin (V9 and Vim 3B4, DAKO, Carpenteria, CA) using 10 pleomorphic adenomas, 10 adenoid cystic carcinomas, and 4 epithelial/myoepithelial carcinomas of the salivary glands. The V9 clone of vimentin was much more efficient in demonstrating the myoepithelial cells in the different tumors studied. The Vim 3B4 clone was capable of detecting some myoepithelial cells, the plasmacytoid or modified myoepithelial cells in the pleomorphic adenoma, but was very weak in epithelial/-myoepithelial carcinomas. The difference between the two clones studied is a warning that pathologists need to know the specificity and sensitivity of the reagent they are using.