P63 is expressed in basal and myoepithelial cells of human normal and tumor salivary gland tissues

Chronic Sclerosing Sialadenitis of the Submandibular Gland and its Histopathological Spectrum in the IgG4-Related Disease: a Series of 17 Cases

PURPOSE

This study aimed to characterize the histopathological immunohistochemical features of chronic sclerosing sialadenitis, emphasizing the IgG4-related disease.

METHODS

Seventeen cases of chronic sclerosing sialoadenitis were examined for histopathological aspects, (inflammation, fibrosis, glandular parenchyma, and lymphoid follicles) and immunohistochemistry (BCL2, CD3, CD20, CD34, CD163, p63, cyclin D1, mast cell, SMA, S100A4, IgG, and IgG4) which were scored. IgG4-related disease features were investigated. Demographic and clinical data were also collected.

RESULTS

Males predominated (10:7), with an average lesion size of 3.9 cm. Common histopathological findings included reduced acinar parenchyma, lymphoid follicle formation, and ductular proliferation. CD3-positive T lymphocytes and CD34- and SMA-positive stromal fibroblasts were abundant. Nine cases (53%) showed sialoliths and three cases met the criteria for IgG4-related disease.

CONCLUSION

CSS of the submandibular gland represents a reactive pattern rather than IgG4-RD as only 3 cases seemed to be related to IgG4-RD. The immunohistochemical profile revealed an abundant population of CD3-positive T lymphocytes, as opposed to regulatory proteins such as cyclin D1, demonstrating that populations of CD34- and SMA-positive stromal fibroblasts contribute to the fibrosis characteristic of CSS. In addition, our results provide a comprehensive insight into the study of CSS and its relationship with IgG4-RD.

Oncocytic Lesions of Salivary Glands: Morphological, Immunohistochemical, and Molecular Findings

The fifth edition of the World Health Organization (WHO) classification introduces new diagnostic methods based on genetic alterations, providing insight into the molecular basis of lesions. As a result, the classification system has evolved, new entities have been introduced, and existing entities have been reclassified. Oncocytic lesions of salivary glands are a group of neoplastic conditions characterized by the presence of oncocytic cells. These lesions present a diagnostic challenge due to their overlapping histological features. Therefore, a comprehensive evaluation, including morphological, immunohistochemical, and molecular analysis, is crucial for accurate diagnosis and appropriate management. Accurate classification of salivary gland pathologies is essential for selecting the appropriate treatment methods and predicting outcomes. The introduction of new therapeutic approaches, such as targeted therapies for malignant salivary gland tumors, has improved patient outcomes. However, to effectively implement these therapies in clinical practice, a clear classification of lesions is necessary.

Malignant Minor Salivary gland neoplasms ofLarynx: Our Experience

<br><b>Introduction:</b> Malignant minor salivary gland tumors are rare, accounting for fewer than 1% of all laryngeal cancers.</br> <br><b>Aim:</b> This study aims to share our experiences regarding clinical, radiological, pathological profiles and their management.</br> <br><b>Materials and methods:</b> The current study reviews 11 cases of malignant minor salivary gland tumors of the larynx treated surgically at our Institute between 2005 and 2019.</br> <br><b>Results:</b> The mean age of the patients was 54 years (range 38-75 years) with six females and five males in the series (1.2:1). Subglottis and trachea were the sites of origin in 54% of the cases, and hoarseness with dyspnea were the most common presenting symptoms. There were nine Adenoid cystic and two Mucoepidermoid carcinoma patients. Surgery was the primary mode of treatment.</br> <br><b>Conclusions:</b> Most of the larynx's malignant minor salivary gland tumors are submucosal in origin. The outcome and prognosis vary considerably based on the tumor's histology, grade, and stage.</br>.

ΔNp63 maintains the fidelity of the myoepithelial cell lineage and directs cell differentiation programs in the murine salivary gland

Salivary glands consist of several epithelial cell types of distinct lineages and functional characteristics that are established by directed differentiation programs of resident stem and progenitor cells. We have shown that ΔNp63, a crucial transcriptional regulator of stem/progenitor cells, is enriched in both the basal and myoepithelial cell (MEC) populations and that ΔNp63 positive cells maintain all the descendent epithelial cell lineages of the adult mouse salivary glands (mSGs). Although this pivotal role of ΔNp63 in driving the broader epithelial cell fate and identity in the mSG has been demonstrated, how ΔNp63 functions specifically in the commitment and differentiation of the MEC population is less understood. Using multiple genetic mouse models that allow for cell tracing, we show that ΔNp63 is critical in maintaining and renewing MECs, in part through the transcriptional regulation of Acta2 gene expression, a defining marker of this cell population. We demonstrate that during adult mSG homeostasis, ΔNp63 enriched MECs function as bipotent progenitor cells that maintain not only the MEC population, but also the distinctly different ductal cell lineages. The fidelity of this process is dependent on ΔNp63 expression, since MEC-specific ablation of ΔNp63 results in altered MEC differentiation and affects cellular plasticity resulting in aberrant differentiation of the intercalated ducts and acinar cells. In contrast, we find that the contribution of MECs to ductal and acinar cell regeneration following severe injury is independent of ΔNp63. Our observations offer new insights into cellular mechanisms driving MEC fate choices and differentiation programs in the context of salivary gland homeostasis and in response to injury and regeneration. Long term, these findings have implications for better treatment of salivary gland dysfunction through stem cell-based approaches.

Mucoepidermoid carcinoma may be devoid of squamoid cells by immunohistochemistry: expanding the histologic and immunohistochemical spectrum of MAML2- rearranged salivary gland tumours

Mucoepidermoid carcinoma (MEC) is historically defined by a mix of squamoid, intermediate, and mucous cells, but we have recently encountered several cases lacking immunoreactivity for squamous markers p40, p63, and CK5/6 despite MAML2 fusions. This study will characterise these unique tumours. Ten MEC were collected arising from the parotid gland (n = 4), submandibular gland (n = 2), nasopharynx (n = 1), base of tongue (n = 1), bronchus (n = 1), and trachea (n = 1). Six tumours were low-grade, two intermediate-grade, one high-grade, and one demonstrated low-grade areas with high-grade transformation. Four cases were oncocytic, four had clear-cell features, two had spindle cell features, and one high-grade MEC had prominent solid, cord-like, and micropapillary features. The tumours were negative for p40 (10/10), p63 (10/10), and CK5/6 (9/9). Targeted RNA sequencing demonstrated CRTC1::MAML2 in five cases, CRTC3::MAML2 in two, and a novel MAML2::CEP126 in the unusual high-grade case. In two cases with insufficient RNA, MAML2 fluorescence in situ hybridisation (FISH) showed rearrangement. Genetically-confirmed MEC may lack overt squamous differentiation by histology and immunohistochemistry. While most cases harboured canonical fusions and fit within the spectra of MEC variants with oncocytic, clear cell, and/or spindle cell features, one had a novel MAML2::CEP126 fusion and unusual morphology. In MEC without squamoid cells, the use of immunohistochemistry may hinder, rather than aid, the correct diagnosis. In such cases, MAML2 analysis is most useful. The historical definition of MEC as a carcinoma with squamoid, intermediate and mucous cells should be revisited.

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.

Primary Mucoepidermoid Carcinoma of the Lacrimal Apparatus

PURPOSE

In this study, we evaluated the clinicopathologic and molecular characteristics of lacrimal apparatus mucoepidermoid carcinoma (MEC) to define its typical diagnostic features.

DESIGN

Retrospective observational case series.

METHODS

Institutional pathology records between 2011 and 2021 were searched for all cases of lacrimal apparatus MEC.

RESULTS

A total of 2 male and 6 female patients ranging in age from 18 to 83 years (median 56, mean 54) were included. Six lacrimal apparatus MECs were found in the lacrimal gland, and 2 cases occurred in the lacrimal sac and nasolacrimal duct. Histologically, there were 6 cases of conventional MEC, 1 clear-cell variant of MEC, and 1 oncocytic variant of MEC for a total of 8 cases. There were 3 low-grade cases and 5 high-grade cases. All 8 cases were evaluated via immunohistochemistry, and the results were positive (scores 1-4) for pankeratin, 34betaE12, p63, p40, CK7, CK8, and CK19, with a relatively higher expression of p63 observed in high-grade MEC. The presence of human papillomavirus (HPV) type 6 DNA was found in 4 patients. MAML2 fluorescence in situ hybridization was positive for MAML2 rearrangement in 3 lacrimal gland tumors (2 low-grade and 1 high-grade). Six tumors were managed with radical resection, and 2 patients underwent orbital exenteration. Postoperative radiation therapy was delivered to 6 patients, and chemotherapy was administered to 1 patient.

CONCLUSIONS

MECs of the lacrimal apparatus are rare tumors, and the rate of MAML2 translocations is lower than that in salivary MECs. Lacrimal gland and lacrimal sac MECs may not be of the same subtypes intrinsically because of the difference in MAML2 translocation, anatomy, and clinical course. The etiologic function of HPV type 6 infection should be explored in lacrimal apparatus MECs. Radical surgery is the treatment of choice. The description of these unique findings may assist in the definitive diagnosis of and improve our understanding of lacrimal apparatus MEC.

MUC1 and Polarity Markers INADL and SCRIB Identify Salivary Ductal Cells

Current treatments for xerostomia/dry mouth are palliative and largely ineffective. A permanent clinical resolution is being developed to correct hyposalivation using implanted hydrogel-encapsulated salivary human stem/progenitor cells (hS/PCs) to restore functional salivary components and increase salivary flow. Pluripotent epithelial cell populations derived from hS/PCs, representing a basal stem cell population in tissue, can differentiate along either secretory acinar or fluid-transporting ductal lineages. To develop tissue-engineered salivary gland replacement tissues, it is critical to reliably identify cells in tissue and as they enter these alternative lineages. The secreted protein α-amylase, the transcription factor MIST1, and aquaporin-5 are typical markers for acinar cells, and K19 is the classical ductal marker in salivary tissue. We found that early ductal progenitors derived from hS/PCs do not express K19, and thus earlier markers were needed to distinguish these cells from acinar progenitors. Salivary ductal cells express distinct polarity complex proteins that we hypothesized could serve as lineage biomarkers to distinguish ductal cells from acinar cells in differentiating hS/PC populations. Based on our studies of primary salivary tissue, both parotid and submandibular glands, and differentiating hS/PCs, we conclude that the apical marker MUC1 along with the polarity markers INADL/PATJ and SCRIB reliably can identify ductal cells in salivary glands and in ductal progenitor populations of hS/PCs being used for salivary tissue engineering. Other markers of epithelial maturation, including E-cadherin, ZO-1, and partition complex component PAR3, are present in both ductal and acinar cells, where they can serve as general markers of differentiation but not lineage markers.

Practical immunohistochemistry in the classification of salivary gland neoplasms

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

Diagnostic utility of p63/p40 in the histologic differentiation of salivary gland tumors: A systematic review

OBJECTIVE

Salivary gland tumors are a heterogeneous group of neoplasms with complex clinicopathologic behavior. These tumors often show an extremely diverse morphology and significant histologic patterns, making diagnosis a difficult task. Owing to the considerable differences in prognosis, treatment, and follow-up, accurately distinguishing these histologic mimickers is imperative. The aim of the present systematic review was to establish the diagnostic utility of p63/p40 immunostaining in histologic differentiation of salivary gland tumors.

STUDY DESIGN

An electronic search was carried out using MEDLINE by PubMed, Scopus, Google Scholar, Trip, Cochrane Library, and EMBASE databases. Articles in which both p63 and p40 immunohistochemical expressions were assessed were included for systematic review and their sensitivity and specificity were calculated. Risk of bias was analyzed for each study using the Quality Assessment of Diagnostic Accuracy Studies tool.

RESULTS

Ten eligible articles were included in the quantitative synthesis, which revealed a concordant positivity of p63 and p40 by nearly all cases of adenoid cystic carcinoma, pleomorphic adenoma, and mucoepidermoid carcinoma and most polymorphous adenocarcinomas showed discordant immunohistochemical expression (p63+/p40-).

CONCLUSIONS

The current evidence supports that integrated immunostaining of p63/p40 is a valuable adjunct for discerning enigmatic salivary gland tumors with true myoepithelial and/or squamous differentiation.

p63 expression in human tumors and normal tissues: a tissue microarray study on 10,200 tumors

Background

Tumor protein 63 (p63) is a transcription factor of the p53 gene family involved in differentiation of several tissues including squamous epithelium. p63 immunohistochemistry is broadly used for tumor classification but published data on its expression in cancer is conflicting.

Methods

To comprehensively catalogue p63 expression, tissue microarrays (TMAs) containing 12,620 tissue samples from 115 tumor entities and 76 normal tissue types were analyzed.

Results

p63 expression was seen in various normal tissues including squamous epithelium and urothelium. At least occasional weak p63 positivity could be detected in 61 (53%) of 115 different tumor types. The frequencies of p63 positivity was highest in squamous cell carcinomas irrespective of their origin (96–100%), thymic tumors (100%), urothelial carcinomas (81–100%), basal type tumors such as basal cell carcinomas (100%), and various salivary gland neoplasias (81–100%). As a rule, p63 was mostly expressed in cancers derived from p63 positive normal tissues and mostly not detectable in tumors derived from p63 negative cancers. However, exceptions from this rule occurred. A positive p63 immunostaining in cancers derived from p63 negative tissues was unrelated to aggressive phenotype in 422 pancreatic cancers, 160 endometrium cancers and 374 ovarian cancers and might be caused by aberrant squamous differentiation or represent stem cell properties. In 355 gastric cancers, aberrant p63 expression occurred in 4% and was linked to lymph node metastasis (p = 0.0208). Loss of p63 in urothelial carcinomas - derived from p63 positive urothelium - was significantly linked to advanced stage, high grade (p < 0.0001 each) and poor survival (p < 0.0001) and might reflect clinically relevant tumor dedifferentiation.

Conclusion

The high prevalence of p63 expression in specific tumor types makes p63 immunohistochemistry a suitable diagnostic tool. Loss of p63 expression might constitute a feature of aggressive cancers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40364-021-00260-5.

Soft Tissue Special Issue: Myoepithelial Neoplasms of Soft Tissue: An Updated Review with Emphasis on Diagnostic Considerations in the Head and Neck

Primary myoepithelial neoplasms of soft tissue have been shown to be related to their salivary gland counterparts, with which they often share morphologic, immunophenotypic, and molecular genetic features, such as the presence of PLAG1 rearrangement in both soft tissue mixed tumor and salivary pleomorphic adenoma. However, important distinctions remain between soft tissue and salivary myoepithelial neoplasms, namely differing criteria for malignancy. This review provides an overview of the current understanding of the clinicopathologic and molecular features of soft tissue myoepithelial neoplasms, including discussion of the similarities and differences between soft tissue and salivary counterparts and relevant diagnostic issues specific to head and neck pathology practice.

Analysis of the Clinical Relevance of Histological Classification of Benign Epithelial Salivary Gland Tumours

INTRODUCTION

A vast increase in knowledge of numerous aspects of malignant salivary gland tumours has emerged during the last decade and, for several reasons, this has not been the case in benign epithelial salivary gland tumours. We have performed a literature review to investigate whether an accurate histological diagnosis of the 11 different types of benign epithelial salivary gland tumours is correlated to any differences in their clinical behaviour.

METHODS

A search was performed for histological classifications, recurrence rates and risks for malignant transformation, treatment modalities, and prognosis of these tumours. The search was performed primarily through PubMed, Google Scholar, and all versions of WHO classifications since 1972, as well as numerous textbooks on salivary gland tumours/head and neck/pathology/oncology. A large number of archival salivary tumours were also reviewed histologically.

RESULTS

Pleomorphic adenomas carry a considerable risk (5-15%) for malignant transformation but, albeit to a much lesser degree, so do basal cell adenomas and Warthin tumours, while the other eight types virtually never develop into malignancy. Pleomorphic adenoma has a rather high risk for recurrence while recurrence occurs only occasionally in sialadenoma papilliferum, oncocytoma, canalicular adenoma, myoepithelioma and the membranous type of basal cell adenoma. Papillomas, lymphadenoma, sebaceous adenoma, cystadenoma, basal cell adenoma (solid, trabecular and tubular subtypes) very rarely, if ever, recur.

CONCLUSIONS

A correct histopathological diagnosis of these tumours is necessary due to (1) preventing confusion with malignant salivary gland tumours; (2) only one (pleomorphic adenoma) has a considerable risk for malignant transformation, but all four histological types of basal cell adenoma can occasionally develop into malignancy, as does Warthin tumour; (3) sialadenoma papilliferum, oncocytoma, canalicular adenoma, myoepithelioma and Warthin tumour only occasionally recur; while (4) intraductal and inverted papilloma, lymphadenoma, sebaceous adenoma, cystadenoma, basal cell adenoma (apart from the membranous type) virtually never recur. No biomarker was found to be relevant for predicting recurrence or potential malignant development. Guidelines for appropriate treatment strategies are given.

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.

Genetic and scRNA-seq Analysis Reveals Distinct Cell Populations that Contribute to Salivary Gland Development and Maintenance

Stem and progenitor cells of the submandibular salivary gland (SMG) give rise to, maintain, and regenerate the multiple lineages of mature epithelial cells including those belonging to the ductal, acinar, basal and myoepithelial subtypes. Here we have exploited single cell RNA-sequencing and in vivo genetic lineage tracing technologies to generate a detailed map of the cell fate trajectories and branch points of the basal and myoepithelial cell populations of the mouse SMG during embryonic development and in adults. Our studies show that the transcription factor p63 and alpha-smooth muscle actin (SMA) serve as faithful markers of the basal and myoepithelial cell lineages, respectively and that both cell types are endowed with progenitor cell properties. However, p63⁺ basal and SMA⁺ myoepithelial cells exhibit distinct cell fates by virtue of maintaining different cellular lineages during morphogenesis and in adults. Collectively, our results reveal the dynamic and complex nature of the diverse SMG cell populations and highlight the distinct differentiation potential of the p63 and SMA expressing subtypes in the stem and progenitor cell hierarchy. Long term these findings have profound implications towards a better understanding of the molecular mechanisms that dictate lineage commitment and differentiation programs during development and adult gland maintenance.

Salivary gland stem cells: A review of development, regeneration and cancer

Salivary glands are responsible for maintaining the health of the oral cavity and are routinely damaged by therapeutic radiation for head and neck cancer as well as by autoimmune diseases such as Sjögren's syndrome. Regenerative approaches based on the reactivation of endogenous stem cells or the transplant of exogenous stem cells hold substantial promise in restoring the structure and function of these organs to improve patient quality of life. However, these approaches have been hampered by a lack of knowledge on the identity of salivary stem cell populations and their regulators. In this review we discuss our current knowledge on salivary stem cells and their regulators during organ development, homeostasis and regeneration. As increasing evidence in other systems suggests that progenitor cells may be a source of cancer, we also review whether these same salivary stem cells may also be cancer initiating cells.

Functional characterization and genomic studies of a novel murine submandibular gland epithelial cell line

A better understanding of the normal and diseased biology of salivary glands (SG) has been hampered, in part, due to difficulties in cultivating and maintaining salivary epithelial cells. Towards this end, we have generated a mouse salivary gland epithelial cell (mSGc) culture system that is well-suited for the molecular characterization of SG cells and their differentiation program. We demonstrate that mSGc can be maintained for multiple passages without a loss of proliferation potential, readily form 3D-spheroids and importantly express a panel of well-established salivary gland epithelial cell markers. Moreover, mSGc 3D-spheroids also exhibit functional maturation as evident by robust agonist-induced intracellular calcium signaling. Finally, transcriptomic characterization of mSGc by RNA-seq and hierarchical clustering analysis with adult organ RNA-seq datasets reveal that mSGc retain most of the molecular attributes of adult mouse salivary gland. This well-characterized mouse salivary gland cell line will fill a critical void in the field by offering a valuable resource to examine various mechanistic aspects of mouse salivary gland biology.

Reduced myofilament component in primary Sjögren's syndrome salivary gland myoepithelial cells

Primary Sjögren's syndrome (pSS) is a solitary poorly understood autoimmune inflammatory disease by involvement of the salivary and lacrimal glands resulting in dry mouth and dry eyes. Myoepithelial cells (MECs) are cells knowing for its hybrid epithelial and mesenchymal phenotype that are important components of the salivary gland (SGs) structure aiding the expulsion of saliva from acinar lobules. In this study we investigate possible alteration in the myofilament component of MECs in SGs specimens obtained from pSS patients in comparison with healthy subjects, to evaluate MECs hypothetical involvement in the pathogenesis of pSS. The expression of alpha-smooth muscle actin (α-SMA) and p63, as MECs markers, was evaluated in bioptic specimens from pSS and healthy labial SGs through immunohistochemistry and immunofluorescence analyses; the distribution of MECs markers was quantified using Aperio ScanScope and ImageScope software to provide quantitative assessments of staining levels. Our observations demonstrated that p63 nuclear labeling in pSS MECs is preserved whereas α-SMA cytoplasmic staining is strongly and significantly reduced when compared with healthy SGs; the digital images analysis quantification of the expression of labeled α-SMA and p63 protein in the healthy and pSS MECs salivary tissues, led to results suggesting a loss of mechanical support for acini and ducts in pSS, correlated, probably, with the reduction of salivary flow that features one important aspect of pSS disease.

Myoepithelioma of Soft Tissue With Both Squamous and Adipocytic Metaplasia

Soft tissue, or cutaneous, myoepitheliomas are rare tumors arising solely from a myoepithelial origin. These neoplasms are typically associated with uncertain differentiation and can contain cellular morphologies that include spindle, plasmacytoid, epithelioid, or clear cell forms. Soft tissue myoepitheliomas are commonly found on the lower limbs and in the pelvic girdle but can occur throughout the body. A small minority display heterogenous differentiation, typically osseous or cartilaginous in nature. Squamous and adipocytic cell types are much rarer. We report the case of myoepithelioma of soft tissue with both squamous and adipocytic metaplasia. In the largest myoepithelioma series of 101 soft tissue myoepitheliomas, there were only 2 cases of squamous metaplasia and 1 case of adipocytic metaplasia. Our case displays the unique occurrence of 2 rare histologic findings occurring simultaneously within an already uncommon neoplasm.

Myoepithelioma of the parotid gland with extensive adipocytic metaplasia: Report of a case with intriguing aspects on fine needle aspiration and p63 immunohistochemical expression

Myoepithelioma is a rare and usually benign salivary gland tumor derived from myoepithelial cells. Variability in cellular morphology and stromal composition leads to diagnostic pitfalls on fine-needle aspiration cytology; therefore, histology and immunohistochemistry are often required for definitive diagnosis. We describe a case of parotid gland myoepithelioma in a 76-year-old woman, which was discovered incidentally on cerebral magnetic resonance imaging. Fine-needle aspiration sampled cohesive aggregates of spindle-shaped cells embedded in a fibrillary matrix as well as abundant mature adipocytes, initially considered as part of normal salivary gland parenchyma. Histology of the resected specimen showed bundles of spindle-shaped cells embedded in loose connective tissue, admixed with numerous intralesional adipocytes. Immunohistochemical studies revealed a diffuse expression of p63 by this adipocytic population, an observation clearly indicating that myoepithelial cells can trans-differentiate and acquire the morphology of mature adipocytes. Knowledge of this phenomenon can be helpful in the work-up of salivary gland lesions. Diagn. Cytopathol. 2016;44:1090-1093. © 2016 Wiley Periodicals, Inc.

p63 Expression in Salivary Gland Tumors: Role ofΔNp73L in Neoplastic Transformation

To illustrate the role of p63 and its truncated variants in salivary gland tumors, 23 consecutive tumors and 6 normal salivary glands were studied immunohistochemically with anti-p63 antibody and by reverse transcriptase (RT) and nested polymerase chain reaction (PCR) to detect p63 isoform expression. Normal salivary glands: p63 antibody-stained basal and myoepithelial cells; by RT and nested PCR, the 2 main isoforms were present, whereas ΔNp73L was absent. Tumors: p63 antibody was positive in the following: Warthin tumor (WT) (3/3), oncocytoma (OC) (1/1), pleomorphic adenoma (PA) (7/7), polymorphous-low-grade adenocarcinoma (PLGA) (3/3), adenoid-cystic carcinoma (ADCC)(3/4), epithelial-myoepithelial-cell carcinoma (EMC) (1/1), and myoepithelial-cell carcinoma (MCC) (1/1). By RT and nested PCR all tumors expressed p63 irrespective of their morphologic differentiation. The ΔNp73L isoform was present in tumoral tissue but absent in normal salivary gland. These data suggest that p63, particularly its splice variant ΔNp73L, is involved in the neoplastic transformation of salivary glands.

Expression of Membrane-Bound Mucins and p63 in Distinguishing Mucoepidermoid Carcinoma from Papillary Cystadenoma

The aim of this study was to compare the immunoexpression of epithelial mucins (MUCs) in salivary duct cysts, papillary cystadenomas, and mucoepidermoid carcinomas and to evaluate if any of these markers could be useful for differentiating between mucoepidermoid carcinoma and papillary cystadenoma. We also sought to validate the p63 expression pattern found to differentiate between mucoepidermoid carcinoma and papillary cystadenoma. Immunoexpression of MUC1, MUC2, MUC4, MUC7, and p63 was studied and quantified in 22 mucoepidermoid carcinomas, 12 papillary cystadenomas, and 3 salivary duct cysts. The immunohistochemical evaluation was collectively performed by 3 oral pathologists. Scores and trends in proportions were assessed using the nonparametric Wilcoxon-Mann-Whitney rank sum test. Mucoepidermoid carcinomas, papillary cystadenomas, and salivary duct cysts demonstrated variable MUC expression patterns. All tumors were positive for p63 immunoexpression with p63 labeling in salivary duct cysts and papillary cystadenomas (15/15) limited to the basal layers of the cystic spaces, whereas in mucoepidermoid carcinomas (22/22) the p63 labeling extended throughout the suprabasal layers (p < 0.001). This study adds more confirmatory data to validate that the reactivity pattern of p63 protein can be used in distinguishing between papillary cystadenoma and low-grade mucoepidermoid carcinoma. Although positive reactivity in a tumor with MUC1 and MUC4 was inconclusive, negative reactivity suggests the diagnosis of a benign PC or SDC.

Characterization of Long-Term Cultured Murine Submandibular Gland Epithelial Cells

PURPOSE

Human and rat salivary gland cell lines derived from tumors or genetic modification are currently available for research. Here, we attempted to culture and characterize long-term cultured cells spontaneously derived from wild type murine submandibular glands (SGs).

METHODS

SGs were removed from 3-week-old C57B/6J female mice and dissociated by collagenase type 1 and hyaluronidase digestion. Isolated SG epithelial cells were cultured in low calcium, serum-free growth media in the presence of cholera toxin (CT) during early passages. Single-cell colonies were isolated by limiting dilution culture after 25 passages. Early- and late-stage cell cultures were characterized for keratin 14, keratin 18, α-smooth muscle actin, and p63 by immunostaining and quantitative real-time PCR analysis.

RESULTS

SG epithelial cells cultured in optimized media maintained their proliferative ability and morphology for over 80 passages. Long-term cultured cells expressed keratin 14, keratin 18, and p63, indicative of an epithelial phenotype.

CONCLUSIONS

Epithelial cells originating from wild type murine SGs could be cultured for longer periods of time and remain phenotypically similar to ductal basal epithelium.

Pathophysiology of myoepithelial cells in salivary glands

Myoepithelial cells (MECs) are considered to be a key participant in most salivary gland diseases, particularly tumors. MECs structurally resemble both epithelial cells and smooth muscles. Diagnostic dilemmas caused are due to inadequacy of characterizing the wide spectrum of morphologic and immunologic features which are different for both normal and neoplastic MECs. This article discusses the development, functions and structure of both normal and neoplastic MECs, their staining properties and differences in the morphologic and immunophenotypic properties of the MEC in detail. It also describes the role of MEC in pathogenesis and morphogenesis of various nonneoplastic and neoplastic salivary gland lesions and thereby are responsible for the myriad histopathology of salivary gland tumors.

Oncocytic Carcinoma of the Submandibular Gland: A Case Report

Oncocytic carcinoma (OC) of the submandibular gland is extremely rare. A 76-year-old man complained of a painless tumor of the right neck. Ultrasonography demonstrated swelling in the lymph nodes of the neck, and fine-needle aspiration cytology of a node showed metastatic carcinoma with oncocytic features. Radical surgery revealed infiltrating carcinoma of the right submandibular gland with lymph node metastases (19/23). Tumor cells showed less atypia and had abundant eosinophilic cytoplasm, which stained deep blue with phosphotungstic acid-hematoxylin stain. The cells were immunohistochemically positive for cytokeratin 7 but negative for p63 and SOX10. We diagnosed the tumor as OC. Chemoradiotherapy was performed after surgery. The patient showed no sign of recurrence until 42 months after the operation, when lymph node swelling was detected in the mediastinum by computed tomography scanning. With no further treatment, the patient is alive with lymph node swellings in the mediastinum and pulmonary hilum 80 months after surgery.

Salivary acinic cell carcinoma: reappraisal and update

Epidemiologic and clinicopathologic features, therapeutic strategies, and prognosis for acinic cell carcinoma of the major and minor salivary glands are critically reviewed. We explore histopathologic, histochemical, electron microscopic and immunohistochemical aspects and discuss histologic grading, histogenesis, animal models, and genetic events. In the context of possible diagnostic difficulties, the relationship to mammary analog secretory carcinoma is probed and a classification is suggested. Areas of controversy or uncertainty, which may benefit from further investigations, are also highlighted.

Myoepithelial Tumors: An Update

Primary myoepithelial neoplasms of soft tissue are uncommon, and have been increasingly characterized by clinicopathologic and genetic means. Tumors are classified as mixed tumor/chondroid syringoma, myoepithelioma, and myoepithelial carcinoma, and they share morphologic, immunophenotypic, and genetic features with their salivary gland counterparts. However, soft tissue myoepithelial tumors are classified as malignant based on the presence of cytologic atypia, in contrast to the criterion of invasive growth in salivary gland sites. This review discusses the clinicopathologic and morphologic characteristics, distinct variants, and currently known genetic alterations of myoepithelial neoplasms of soft tissue, skin, and bone.

Myoepithelial cells in pathology

Myoepithelial cells are a normal constituent of the salivary acini and ducts and are found between the epithelial cells and the basement membrane. Microscopically myoepithelial cells are thin and spindle-shaped and ultrastructurally they possess a number of Cytoplasmic processes that extend between and over the acinar and ductal-lining cells, and they show features of both smooth muscle and epithelium. They play a vital role during expulsion of saliva and regulates the electrolytic exchange. They also perform as tumor suppressors and are considered to play a very important role in differentiation of various salivary gland tumors and help in the diagnosis of tumors. Neoplastic myoepithelial cells in both benign and malignant tumors can take numerous forms including epithelioid, plasmacytoid, spindle and clear cell variant, and this variability largely accounts for difficulties in histopathological diagnosis.

Myoepithelial Carcinoma of the Salivary Glands: A Clinicopathologic Study of 29 Patients

PURPOSE

Myoepithelial carcinomas (MECs) of the salivary glands are relatively rare. The clinicopathologic features, immunohistochemical profile, and biologic behavior have not been well-defined.

MATERIALS AND METHODS

A total of 29 patients with MEC diagnosed during a 10-year period were included in the present study focusing on the biologic behavior, and the pathologic samples of 28 patients were collected for additional investigation of the histologic characteristics. Thirteen samples with detailed immunohistochemical results were included for illustrating immunohistochemical profiles.

RESULTS

The parotid gland (n = 7) was the most common site involved, followed by the palate (n = 6) and the submandibular gland (n = 6). A multinodular growth pattern (n = 14) and sheet-like arrangement of tumor cells (n = 14) were observed. Of the 28 MEC samples, 14 (50%) were epithelioid, 5 (18%) were clear cell, 5 (18%) were plasmacytoid, 3 (11%) were mixed cell type, and 1 (3%) was spindle. The tumor-associated matrix was more prevalently hyalinized than myxoid. Of the 28 cases, 12 (43%) were classified as high grade and 16 (57%) as low grade. Immunohistochemical analysis revealed pan-cytokeratin (92.3%), smooth muscle actin (36%), S-100 protein (54.5%), and p63 (91.7%) positivity and carcinoembryonic antigen (100%) negativity. Ki-67 was immunoreactive in 62% of the MECs, with the Ki-67 labeling index ranging from less than 5 to 20%. Eleven patients developed recurrence (median disease-free survival 43 months) and 11 (44%) developed metastases. Two patients (8%) died of disease after a mean period of 18 months. Fourteen patients (61%) were without any evidence of disease after a mean of 32.5 months (range 3 to 86). The mitotic rate correlated weakly (P = .042) with a poor outcome, but none of the other factors showed a significant correlation with the prognosis.

CONCLUSION

MECs of the salivary glands have a relatively high recurrence rate and metastasis rate and a long period of survival with tumor. A combination of pathologic features and various immunohistochemical indexes are crucial for the accurate diagnosis of MECs. Extensive excision is the favorable choice for treating MECs, and suprahyoid lymph node dissection is recommended when the submandibular gland is involved.

A comparative immunohistochemistry study of diagnostic tools in salivary gland tumors: usefulness of mammaglobin, gross cystic disease fluid protein 15, and p63 cytoplasmic staining for the diagnosis of mammary analog secretory carcinoma?

BACKGROUND

Mammary analog secretory carcinoma (MASC) of the salivary gland has been recently described according to morphological, immunohistochemical, and molecular (ETV6-NTRK3 translocation) similarities with the mammary secretory carcinoma. The most important differential diagnostic considerations of MASC are low-grade adenocarcinoma not otherwise specified (NOS), cystadenocarcinoma, and acinic cell carcinoma (AciCC). These tumors may share an overlapping morphology with MASC, and additional immunohistochemical studies are required to reinforce the diagnosis. Mammaglobin, GCDFP-15, and p63 staining have been reported in MASC. Our study was designed to check the specificity of these antibodies in MASC compared to other frequent tumors of salivary glands.

METHODS

A series of 62 salivary gland tumors [10 MASCs, 5 adenocarcinomas NOS and 2 cystadenocarcinomas with MASC features and without ETV6 rearrangement, one low-grade cribriform cystadenocarcinoma (LGCCC), 9 AciCCs, 10 MECs, 10 adenoid cystic carcinomas (AdeCCs), 5 polymorphous low-grade adenocarcinomas (PLGAs), and 10 pleomorphic adenomas (PAs)] was analyzed by immunohistochemistry with mammaglobin, GCDFP-15, and p63 antibodies.

RESULTS

Positivity for mammaglobin was observed in all MASCs, cystadenocarcinomas, LGCCC, and PLGAs, in some adenocarcinomas NOS, PAs, and MECs, rarely in AciCCs and never in AdeCCs. Positivity for GCDFP-15 was observed in most of the tumor types except in AdeCCs. Interestingly, cytoplasmic positivity for p63 was observed in most of MASCs and PLGAs while rarely in adenocarcinomas NOS and PAs, and never in the other tumor types.

CONCLUSION

Our study revealed the usefulness of mammaglobin and p63 cytoplasmic staining to define which tumors are worth to be screened for ETV6 rearrangement.

Myoepithelial neoplasms of soft tissue: an updated review of the clinicopathologic, immunophenotypic, and genetic features

Myoepithelial tumors in skin and soft tissue are uncommon but have been increasingly characterized over the past decade. Men and women are equally affected across all age groups and lesions arise most frequently on the extremities and limb girdles. Approximately 20 % of cases occur in pediatric patients, in whom they are frequently malignant. Similar to their salivary gland counterparts, myoepithelial tumors of soft tissue demonstrate heterogeneous morphologic and immunophenotypic features. Tumors are classified as mixed tumor/chondroid syringoma, myoepithelioma, and myoepithelial carcinoma; in soft tissue, tumors having at least moderate cytologic atypia are classified as malignant. Mixed tumor and myoepithelioma show a benign clinical course, with recurrence in up to 20 % (typically secondary to incomplete excision), and do not metastasize. In contrast, myoepithelial carcinoma shows more aggressive behavior with recurrence and metastasis in up to 40-50 % of cases. The majority of myoepithelial neoplasms typically coexpress epithelial antigens (cytokeratin and/or EMA) and S-100 protein; GFAP and p63 are frequently positive and a subset of malignant neoplasms lose INI1 expression. Up to 45 % of myoepitheliomas and myoepithelial carcinomas harbor EWSR1 gene rearrangements, unlike mixed tumor/chondroid syringoma which is characterized by PLAG1 gene rearrangement. While mixed tumor/chondroid syringoma are likely related to primary salivary myoepithelial tumors, soft tissue myoepithelioma and myoepithelial carcinoma appear to be pathologically distinct neoplasms.

Review and Updates of Immunohistochemistry in Selected Salivary Gland and Head and Neck Tumors

Context

Immunohistochemistry is a useful tool for diagnosing salivary gland and head and neck tumors.

Objective

To review immunohistochemical markers, which can aid in the diagnosis of selected salivary gland and head and neck tumors.

Data Sources

Literature review and authors' personal practice experience.

Conclusions

Salivary gland and head and neck tumors include a large diverse group of tumors with complex and overlapping histologic features. Immunohistochemistry plays an important role in resolving the differential diagnosis of some salivary gland and head and neck tumors and can provide information for the prognosis of certain tumors.

DOG1, p63, and S100 protein: a novel immunohistochemical panel in the differential diagnosis of oncocytic salivary gland neoplasms in fine-needle aspiration cell blocks

INTRODUCTION

DOG1 is a calcium-activated chloride channel protein that may have a potential role in secretory cells of salivary glands and tumors derived from them. Its role in cytologic specimens is not well documented. This study was performed to evaluate its utility in separating acinic cell carcinoma (AciCC) from other closely related differential diagnoses on cytologic samples. In addition, an immunohistochemical panel consisting of DOG1, p63, and S100 protein to assist in the subclassification of these salivary gland neoplasms with oncocytic differentiation was also investigated.

MATERIALS AND METHODS

Thirty-one fine-needle aspiration cell blocks (CBs) of oncocytic salivary gland neoplasms (16 Warthin tumors [WTs], 10 AciCCs, 3 mucoepidermoid carcinomas [MECs], and 2 oncocytomas [ONCs]), and 75 salivary gland resections (7 WTs, 27 AciCCs, 36 MECs, 2 high-grade adenocarcinomas, 2 ONCs, 1 papillary cystadenoma) were immunostained for DOG1, p63, and S100.

RESULTS

DOG1 and p63 were very useful in distinguishing AciCC from WT on CB, because 100% of WTs were DOG1-negative and 87.5% were p63-positive, whereas 70% of AciCCs were DOG1-positive and 100% were p63-negative. The resection results correlated with those on CBs: 100% of WTs were DOG1-negative and 86% were p63-positive, whereas 93% of AciCCs were DOG1-positive and 89% were p63-negative. S100 and DOG1 were negative in both WTs and ONCs, with <10% S100 positivity in AciCCs.

CONCLUSIONS

DOG1 was very helpful in separating AciCC from WT, MEC, and ONC. In summary, an immunohistochemical panel including DOG1, p63, and S100 can significantly improve the accuracy of diagnosing oncocytic salivary gland neoplasms on CBs.

Histopathologic, immunophenotypic and cytogenetic features of pulmonary mucoepidermoid carcinoma

Pulmonary mucoepidermoid carcinoma is an uncommon but distinctive manifestation of mucoepidermoid carcinoma. Pulmonary mucoepidermoid carcinoma occurs in adults and children and can cause diagnostic problems, especially in small biopsies. Few studies have characterized the histologic and immunophenotypic features of pulmonary mucoepidermoid carcinoma. t(11;19)(q21;p13) is considered disease-defining for mucoepidermoid carcinoma; its significance in pulmonary mucoepidermoid carcinoma warrants further study. Forty three pulmonary mucoepidermoid carcinomas were re-reviewed and graded according to the Brandwein grading system for mucoepidermoid carcinoma. Four cases were excluded because of a split opinion between pathology report and re-review. These cases were negative for MAML2 rearrangement by FISH. TTF-1, napsin A, p40 and p63 immunostains were scored: 0 (negative), 1 (1-25% tumor cells), 2 (26-50%), 3 (51-75%) or 4 (>75%). FISH to detect MAML2 rearrangement used a MAML2-11q21 break-apart probe. Thirty nine pulmonary mucoepidermoid carcinoma (4 low, 30 intermediate, 5 high grade) contained mucous, epidermoid and intermediate cells and lacked keratinization and in situ carcinoma of the overlying epithelium. All cases with available gross description (n=22) had a central/endo- or peribronchial location. All 25 cases tested for immunohistochemistry were positive (scores 1-4) for p63; 23 also expressed p40. In six cases, the p63 score was higher than p40. TTF-1 and napsin were uniformly negative in all 25 cases. MAML2 rearrangement was identified by FISH in each of the 24 cases tested (3 low, 19 intermediate, 2 high grade). Clinical history was available in 29 patients (15 men) (median age, 48 years) with follow-up in 24 (median, 8.4 years). Five patients died of unrelated causes; one developed metastatic pulmonary mucoepidermoid carcinoma. In conclusion, features helpful in distinguishing pulmonary mucoepidermoid carcinoma from other lung cancers include its central/endo- or peribronchial location together with the presence of mucous cells, p63 expression, lack of keratinization and MAML2 rearrangement. TTF-1 and napsin are typically not expressed.

Sox2 regulates the emergence of lung basal cells by directly activating the transcription of Trp63

Lung development is determined by the coordinated expression of several key genes. Previously, we and others have shown the importance of the sex determining region Y-box 2 (Sox2) gene in lung development. Transgenic expression of Sox2 during lung development resulted in cystic airways, and here we show that modulating the timing of ectopic Sox2 expression in the branching regions of the developing lung results in variable cystic lesions resembling the spectrum of the human congenital disorder congenital cystic adenomatoid malformation (CCAM). Sox2 dominantly differentiated naive epithelial cells into the proximal lineage irrespective of the presence of Fgf10. Sox2 directly induced the expression of Trp63, the master switch toward the basal cell lineage and induced the expression of Gata6, a factor involved in the emergence of bronchoalveolar stem cells. We showed that SOX2 and TRP63 are coexpressed in the lungs of human patients with type II CCAM. The combination of premature differentiation toward the proximal cell lineage and the induction of proliferation resulted in the cyst-like structures. Thus, we show that Sox2 is directly responsible for the emergence of two lung progenitor cells: basal cells by regulating the master gene Trp63 and bronchoalveolar stem cells by regulating Gata6.

Canalicular adenoma: a clinicopathologic and immunohistochemical analysis of 67 cases with a review of the literature

There is a lack of a comprehensive immunohistochemical (IHC) analysis of canalicular adenoma (CanAd), especially when combined with a description of the unique histologic features. Given the usual small biopsies, IHC may be useful in distinguishing CanAd from other tumors in the differential diagnosis. Retrospective. The patients included 54 females and 13 males (4.2:1), aged 43-90 years, with a mean age at presentation of 69.9 years. Clinical presentation was generally a mass (n = 61) slowly increasing in size (mean 38.5 months), affecting the upper lip (n = 46), buccal mucosa (n = 17) or palate (n = 4), involving the right (n = 29), left (n = 24) or midline (n = 9), without any major salivary gland tumors. The tumors ranged in size from 0.2 to 3 cm (mean 1.2 cm). Most tumors were multilobular or bosselated (76 %), often surrounded by a capsule. Histologically, the tumors were characterized by cystic spaces, tumor cords with beading, tubule formation, and by the presence of luminal squamous balls (n = 41). The cells were cuboidal to columnar with stippled chromatin. Mitoses were inconspicuous. A myxoid stroma (n = 64), sclerosis (n = 42), luminal hemorrhage (n = 51), and luminal microliths (calcifications) (n = 33) were characteristic. Nine (13.4 %) were multifocal. CanAd showed the following characteristic immunohistochemistry findings: CK-pan and S100 protein (strong, diffuse reaction); peripheral or luminal GFAP reaction; CK5/6 and p16 luminal squamous ball reaction; SOX10 nuclear reaction; cytoplasmic p63 reaction. CanAd are unique minor salivary gland tumors showing a distinct architecture and phenotype. They predilect to older women, with the majority multilobulated and affecting the upper lip, multifocal in 13 %; no major salivary gland tumors were identified. S100 protein, CK-pan, GFAP and SOX10 are positive, with luminal squamous balls highlighted by CK5/6 or p16.

Expression and localization of osteopontin, homing cell adhesion molecule/CD44, and integrin αvβ3 in pleomorphic adenoma, polymorphous low-grade adenocarcinoma, and adenoid cystic carcinoma

OBJECTIVES

Osteopontin (OPN) plays a role in tumor progression. This study aimed to determine the expression of OPN, CD44, and integrin αvβ3 in pleomorphic adenoma (PA), polymorphous low-grade adenocarcinoma (PLGA), and adenoid cystic carcinoma (ACC).

STUDY DESIGN

Immunohistochemistry was used to semiquantify the level of expression of OPN and its receptors in normal salivary glands (NSG; n = 20), PA (n = 20), PLGA (n = 16), and ACC (n = 22).

RESULTS

OPN expression was increased in PLGA and intermediate-/high-grade ACC compared with PA and NSG (median scores, 6, 5, 4, and 4, respectively). CD44 expression was reduced in PA, PLGA, and ACC. OPN expression levels were moderately correlated with CD44 in PLGA. Integrin αvβ3 was not expressed in PA and ACC and was seen in only 1 case of PLGA.

CONCLUSIONS

OPN is expressed in salivary gland tumors but does not correlate well with CD44 and αvβ3.

Expression and localization of osteopontin, homing cell adhesion molecule/CD44, and integrin αvβ3 in mucoepidermoid carcinoma and acinic cell adenocarcinoma of salivary gland origin

OBJECTIVE

Osteopontin (OPN) plays a role in tumor progression. This study aimed to determine the expression of OPN, CD44, and integrin αvβ3 in pleomorphic adenoma (PA), acinic cell adenocarcinoma (ACA), and mucoepidermoid carcinoma (MEC).

STUDY DESIGN

Immunohistochemistry was used to semiquantify the levels of expression of OPN and its receptors in normal salivary glands (NSG) (n = 20), PA (n = 20), ACA (n = 11), and MEC (n = 29).

RESULTS

OPN expression was increased in ACA and MEC compared with PA and NSG (median scores, 6, 6, 4, and 4, respectively). CD44 expression was increased in ACA and reduced in MEC and PA compared with NSG (median scores, 8, 4, 3, and 5, respectively). Integrin αvβ3 median scores were 5 in ACA, 1 in MEC, and 0 in PA and NSG.

CONCLUSIONS

OPN is expressed in salivary gland tumors and is at higher levels in ACA and MEC.

A comprehensive comparative analysis of the histomorphological features of ALK-rearranged lung adenocarcinoma based on driver oncogene mutations: frequent expression of epithelial-mesenchymal transition markers than other genotype

Molecular classification of lung cancer correlates well with histomorphological features. However, specific histomorphological features that differentiate anaplastic lymphoma kinase (ALK)-rearranged tumors from ALK-negative tumors have not been fully evaluated. Eighty ALK-rearranged and 213 ALK-negative (91 epidermal growth factor receptor-mutated; 29 K-ras-mutated; 93 triple-negative) resected lung adenocarcinomas were analyzed for several histomorphological parameters and histological subtype. ALK-rearranged tumors were associated with younger age at presentation, frequent nodal metastasis, and higher stage of disease at diagnosis. ALK-rearranged tumors were more likely to show a solid predominant pattern than ALK-negative tumors (43.8%; 35/80; p<0.001). Unlike ALK-negative tumors, a lepidic predominant pattern was not observed in ALK-rearranged tumors (p<0.001). In multivariate analysis, the most significant morphological features that distinguished ALK-rearranged tumors from ALK-negative tumors were cribriform formation (odds ratio [OR], 3.253; p = 0.028), presence of mucin-containing cells (OR, 4.899; p = 0.008), close relationship to adjacent bronchioles (OR, 5.361; p = 0.001), presence of psammoma bodies (OR, 4.026; p = 0.002), and a solid predominant pattern (OR, 13.685; p = 0.023). ALK-rearranged tumors exhibited invasive histomorphological features, aggressive behavior and frequent expression of epithelial-mesenchymal transition markers (loss of E-cadherin and expression of vimentin) compared with other genotype (p = 0.015). Spatial proximity between bronchus and ALK-rearranged tumors and frequent solid histologic subtype with p63 expression may cause diagnostic difficulties to differentiate squamous cell carcinoma in the small biopsy, whereas p40 was rarely expressed in ALK-rearranged adenocarcinoma. Knowledge of these features may improve the diagnostic accuracy and lead to a better understanding of the characteristic behavior of ALK-rearranged tumors.

P63 expression in papillary cystadenoma and mucoepidermoid carcinoma of minor salivary glands

OBJECTIVE

The aim of this study was to investigate the expression of p63 protein in mucoepidermoid carcinoma and papillary cystadenoma of the salivary glands, and to evaluate the usefulness of this protein in distinguishing these tumors.

STUDY DESIGN

Immunoexpression of p63 protein was studied and quantified in 9 formalin-fixed paraffin-embedded mucous retention cysts, 4 papillary cystadenomas, and 19 low-grade and 9 high-grade mucoepidermoid carcinomas.

RESULTS

All cases were positive for p63 immunoexpression; however, it was observed that p63 labeling in mucous retention cysts and papillary cystadenomas was limited to the basal layers of the cystic spaces, whereas in low-grade mucoepidermoid carcinomas, positive nuclear staining was also found diffusely in the suprabasal layers. Mucoepidermoid carcinoma presented increased immunoexpression of p63 compared with the other groups.

CONCLUSIONS

P63 immunohistochemical expression pattern can be helpful in distinguishing low-grade mucoepidermoid carcinoma from papillary cystadenoma of the salivary glands.

Podoplanin is a novel myoepithelial cell marker in pleomorphic adenoma and other salivary gland tumors with myoepithelial differentiation

The expression of podoplanin, one of the representative immunohistochemical markers for lymphatic endothelium, is upregulated in various kinds of cancers. Based on our previous studies, we have developed a hypothesis that podoplanin plays a role in cell adhesion via its association with extracellular matrix (ECM). Since salivary pleomorphic adenoma is histologically characterized by its ECM-enriched stroma, we firstly wanted to explore the expression modes of podoplanin in pleomorphic adenoma and related salivary tumors by immunohistochemistry. In normal salivary gland, podoplanin was specifically localized in myoepithelial cells, which were also positively labeled by antibodies against P63, of the intercalated duct as well as acini. In pleomorphic adenoma, podoplanin was colocalized with P63 and CD44 in basal cells of glandular structures as well as in stellate/spindle cells in myxochondroid matrices, where perlecan and hyaluronic acid were enriched. The expression of podoplanin was confirmed at both protein and mRNA levels in pleomorphic adenoma cell systems (SM-AP1 and SM-AP4) by using immunofluorescence, western blotting, and reverse transcription polymerase chain reaction. Podoplanin was localized on the cell border as well as in the external periphery of the cells. Moreover, podoplanin expression was also confirmed in tumor cells with myoepithelial differentiation in myoepithelioma and intraductal papilloma. The results indicate that podoplanin can be regarded as a novel myoepithelial marker in salivary gland tumors and suggest that podoplanin's communication with ECM molecules is essential to phenotypic differentiation to myoepithelial cells.

The Molecular Pathology of Salivary Gland Tumors with Translocations

Presented here are the salivary gland tumors now recognized to have significant and highly prevalent translocations. These include both common and uncommon malignancies: mucoepidermoid carcinoma, adenoid cystic carcinoma, mammary analog secretory carcinoma, and clear cell carcinoma. These mutations have potential diagnostic applications, particularly in difficult and challenging variant morphologies are unusually challenging differential diagnoses. Practical applications of the molecular pathology of these tumors is discussed. The mutational assessment may also prove to have therapeutic importance, as targeted therapies may be generated for these tumors in the future.

P63 expression can be used in differential diagnosis of salivary gland acinic cell and mucoepidermoid carcinomas

Differentiation of salivary gland acinic cell carcinoma from mucoepidermoid carcinoma can be diagnostically challenging as both may have prominent mucin production. P63 is a p53 homologue required for limb and epidermal morphogenesis. It is expressed in basal and myoepithelial cells of normal salivary gland tissues. In this immunohistochemical study, we examined the expression of p63 in salivary gland acinic cell and mucoepidermoid carcinomas (MEC) and its use in differentiating these two entities. A search was performed and appropriate cases were selected from Lifespan Hospital System archives as well as the consult archives of one author (DRG). 31 salivary gland acinic cell carcinomas (ACC) and 24 MEC were examined for p63 expression by immunohistochemistry. The nuclear immunoreactivity was examined by both authors and was graded semi-quantitatively with negative being less than 10 % of cells staining. Positive staining was graded as follows: 10-25 % of tumor cells staining was weakly positive, 26-75 % of tumor cells staining was moderately positive, and 76-100 % of tumor cells staining was strongly positive. Negative nuclear staining of the tumor cells was seen in 30/31 (96 %) of salivary gland ACC while 1/31 (3 %) showed diffuse nuclear staining of the tumor cells. This latter case was later reclassified as mammary analogue secretory carcinoma following confirmatory molecular testing for the ETV6-NTRK3 fusion gene. Strong positive nuclear staining of the tumor cells was seen in 24 (100 %) of salivary gland MEC cases. P63 is an immunohistochemical stain that can potentially aid in differentiating unusual ACC with prominent mucin production from MEC of the salivary gland. According to this study, acinic cell carcinoma is always negative for p63 immunoreactivity while mucoepidermoid carcinoma is always positive.

Adenocarcinoma of the parotid salivary gland in a cow

A 6-year-old Girolando dairy cow was presented for evaluation of a large subcutaneous facial mass. Fine-needle aspirates of the mass contained many neoplastic cells with high nuclear:cytoplasmic ratios arranged in sheets and loosely cohesive clusters with streaming erythrocytes and neutrophils in the background. Neoplastic cells were 13-25 μm in diameter and were round to cuboidal with variably distinct borders. Based on the signalment, anatomic location, and cytologic findings, differential diagnoses included salivary adenocarcinoma, squamous cell carcinoma, and mucoepidermoid carcinoma. The cow was euthanized and a necropsy was performed. The primary neoplasm arose from the left parotid salivary gland and meastatic tumor was found in the regional lymph nodes and lung. Histologically, the tumor was composed of anastomosing and irregular solid islets surrounded by scant stroma. Cells were negative for periodic acid-Schiff (PAS), PAS-diastase, and Alcian blue pH 2.5 stains, used to detect mucin. On immunohistochemical analysis, neoplastic luminal salivary gland cells expressed cytokeratin, but not S100, α-smooth muscle actin, or vimentin. Peripheral cells of neoplastic islets were immunoreactive for p63. The final diagnosis was nonsecretory adenocarcinoma of the parotid salivary gland.

Sinonasal seromucinous hamartoma: a review of the literature and a case report with focal myoepithelial cells

Seromucinous hamartoma is a benign lesion of the sinonasal tract. Since its description in 1974, only a small number of additional cases have been reported. It is composed of a proliferation of seromucinous glands and ducts within a variable fibrous stroma. The serous component typically stains positively for S100 (at least focally) and lacks p63 positive abluminal cells. The lack of myoepithelial/basal cells is an important diagnostic feature of seromucinous hamartoma; their absence could lead to an incorrect diagnosis of low-grade sinonasal adenocarcinoma. We report the case of a polypoid mass resected from the posterior nasal cavity and nasopharynx of a 54-year-old woman. The lesion contained a population of small and large glands lined by cuboidal to flattened cells within a hypocellular stroma varying from dense and sclerotic to myxoid. Additionally, there was a superficial focus of ciliated invaginated surface epithelium and glands. Throughout the lesion there were no cytologic or architectural features of malignancy. The histologic features were diagnostic of seromucinous hamartoma. Immunohistochemistry showed focal S100 positivity of the serous glands. However, in contrast to previously reported cases, the glands focally showed an outer basal layer that was calponin, p63 and actin positive. Our case demonstrates two important points. First, complete absence of p63 staining should not necessarily be a required feature in the diagnosis of seromucinous hamartoma. Second, the ciliated larger glands--in keeping with respiratory epithelial adenomatoid hamartoma (REAH)--support the suggestion that seromucinous hamartoma and REAH are a spectrum of lesions, often seen together.