The myoepithelial immunophenotype in 135 benign and malignant salivary gland tumors other than pleomorphic adenoma

Bronchial oncocytic carcinoma in an adult: a case report and literature review

BACKGROUND

Lung salivary-type tumors originating from bronchial submucosal glands are rare, only four types of salivary gland-type tumors are listed in 2015 WHO classification of lung tumors. Here, we report a rare case of oncocytic carcinoma (OC) in the right main bronchus.

CASE PRESENTATION

A 34-year-old man presented to our hospital with a two-month history of recurrent hemoptysis and with one month of inspiratory dyspnea. Pulmonary function tests showed mild restrictive ventilatory dysfunction and severe diffusion dysfunction. Furthermore, the flow volume loop showed a variable extra-thoracic obstruction. Computed tomography (CT) of the chest revealed that a polypiform nodule of 13 mm in diameter was at the proximal right main bronchus. Testing for purified protein derivative was positive (category 2). The nodule was resected under bronchoscopy. The bronchial aspirate was negative for mycobacterium tuberculosis and tumor cells. The biopsy sample showed a solid and acinar predominant pattern with abundant eosinophilic cytoplasm. The bronchial mucosa was destroyed and replaced by tumor cells. The loose edematous stromal reaction could be seen in a local area. Immunohistochemically, tumor cells were positive for CK, EMA, Vimentin, CD117, CK7, S100, Mammaglobin and SOX10. Only scattered tumor cells were stained by basal cell markers, including CK5/6, P40 and P63. Electron microscopy revealed numerous swelling mitochondria with lacking mitochondrial cristae in tumor cells. Fluorescence in situ hybridization (FISH) testing for MAML2 and ETV6 rearrangement were negative. Next-generation sequencing analysis of 520 genes in the tissue biopsy specimen showed no somatic mutation. The diagnosis of OC was made. Subsequently, the patient underwent a right upper lobectomy with sleeve resection of the main bronchus and lymph dissection. No recurrent evidence was seen during two years of chest CT follow-up.

CONCLUSIONS

To our knowledge, this is the first case of primary OC in the bronchus. This patient has no recurrence during two years of follow-up, indicating that primary OC in the bronchus has the same favorable prognosis as in salivary glands. Moreover, complete excision and thorough sampling to know the invasive growth pattern is important to reach the correct diagnosis.

Intraosseous clear cell mucoepidermoid carcinoma: A case report and evaluation

Salivary gland tumours 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 tumour entities. One such group of variations is clear cell tumours of oral cavity which constitute an assorted group of lesions that may be odontogenic or metastatic or of salivary gland origin. The clear cell variant of mucoepidermoid carcinoma is at times misleading to the clinician because of its atypical location and innocent appearance. The pathologist needs to be familiar with the molecular alterations so that there may be a strong potential to implement good treatment. Hereby, we report a rare case of intraosseous clear cell variant of mucoepidermoid carcinoma which histopathologically posed challenges due to its variable presentation, suggesting the need for histochemical stains and molecular work-up for a definitive diagnosis and a better therapeutic and prognostic insight.

The Decline of Salivary Adenocarcinoma Not Otherwise Specified as a Tumor Entity: Reclassification Using Contemporary Immunohistochemical Profiling and Diagnostic Criteria

The classification of salivary gland carcinomas has become increasingly specific over the last decade with the definition of new tumor types, documentation of novel molecular and immunohistochemical findings, and development of more refined diagnostic criteria. In this setting, it is unclear how many salivary tumors still cannot be easily categorized-and whether such tumors represent undifferentiated malignancies or include additional definable entities. Relying largely on current classification schemes and contemporary immunohistochemical panels, we reassessed salivary tumors previously diagnosed as adenocarcinoma, not otherwise specified (ACA NOS) from 2 large academic medical centers. Fifty-seven ACA NOS (72%) could be reclassified as more specific entities including 31 salivary duct carcinomas (39%), 7 polymorphous adenocarcinomas (9%), 5 epithelial-myoepithelial carcinomas (6%), 4 myoepithelial carcinomas (5%), 4 secretory carcinomas (5%), 1 acinic cell carcinoma (1%), 1 basal cell adenocarcinoma (1%), 1 intraductal carcinoma (1%), and 1 clear cell carcinoma (1%) as well as 2 metastatic squamous cell carcinomas (3%). Of reclassified cases, 21 (37%) represented variant histologies within these categories. ACA NOS comprised 11% of salivary malignancies before reclassification, but only 4% after reclassification. The remaining 22 ACA NOS demonstrated heterogeneous features, with an association between histologic grade and clinical outcome. In effect, ACA NOS is becoming a bygone entity as modern classification schemes and ancillary techniques now permit more specific typing of a majority of these tumors, potentially facilitating more specific prognostication and treatment. Additional distinctive entities such as mucinous adenocarcinoma may still be definable within the ACA NOS category.

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.

Expression of α-smooth muscle actin in benign and malignant salivary gland tumors: An immunohistochemical study

Background and Objectives

Myoepithelial cells (ME) are known to contribute in the patterning of salivary gland neoplasms (SGN) and possess cytoplasmic smooth muscle actin (SMA) revealed by alpha SMA (α-SMA). The present study aimed to assess the expression of α-SMA in selected benign and malignant SGN (pleomorphic adenoma [PA], mucoepidermoid carcinoma (MEC), adenoid cystic carcinoma (ACC), and polymorphous low-grade adenocarcinoma (PLGA).

Materials and Methods

The intensity and pattern of expression of α-SMA were studied in 25 cases of SGN's ACC (n = 7), MEC (n = 8), PA (n = 8), and PLGA (n = 2), and correlated with the histological patterns.

Results

Maximum expression of α-SMA in the epithelial compartment was seen in ACC, followed by PA, whereas MEC and PLGA showed completely negative staining. The connective tissue expression was mild in ACC and MEC. The myxoid stroma of PA with "melting" pattern was weakly positive for α-SMA. The stroma in PLGA showed complete negativity. In ACC, α-SMA-positive cells were lining the cribriform spaces, small islands, and dispersed within large islands. Small nests showed complete positivity for α-SMA.

Interpretation and Conclusion

In ACC, α-SMA expression supports the involvement of ME in epithelial organization explaining the histological patterns seen. In PA, the expression correlates with the predominantly secretory nature of ME. The absence of epithelial positivity in MEC and PLGA suggest that ME has less role to play in their histogenesis. The weak stromal positivity observed in MEC and ACC may be attributed to the positive immunoreactivity of myofibroblasts playing a role in modulating the course of SGN's.

Immunohistochemical evaluation of salivary gland tumors differentiation and proliferation by using calponin and telomerase

Background

Salivary gland tumors are a heterogeneous group of lesions with diverse histological features. Hence they are considered as a diagnostic challenge for the pathologist. Myoepithelial cells are considered as a key in the morphogenetic process, with diverse differentiation in various salivary gland tumors. Calponin is an actin filament- associated protein that represents a sensitive marker of myoepithelial cells. Telomerase is a ribonucleoprotein that adds telomere repeats at the end of chromosomes in order to prevent replicative senescence. It has a key role in cellular immortality and tumorgenesis of various tumors. This study evaluates the immunohistochemical expression of calponin and telomerase in various salivary gland tumors.

Methods

This retrospective study involved 30 formalin fixed paraffin embedded blocks of salivary gland tumors. The immunohistochemical staining and evaluation of subcellular localization, pattern, intensity, and distribution for calponin and immune scoring for telomerase were done. The statistical analyses of data were conducted by Chi-square and ANOVA-test, a P-value of <0.05 was considered significant.

Results

Calponin showed expression at the periphery of acini and intercalated ducts in the normal salivary gland. It revealed cytoplasmic expression in 83.3% of benign tumors. The pleomorphic adenoma showed a diffuse pattern of staining (85.7%), strong intensity (64.3%), and mixed distributions (57.1%). The diffuse pattern of calponin was seen in all cases of mucoepidermoid, polymorphous low-grade adenocarcinoma and epithelial-myoepithelial carcinoma (100%). Telomerase revealed negative expression in the normal salivary gland. Pleomorphic adenoma illustrated high telomerase expression in score 2 and score 3 (93.3%). Telomerase immune scoring is significantly related to the benign tumors as P value was 0.03. Both polymorphous low grade and epithelial-myoepithelial carcinoma were detected only in score 3. Finally, the mean level of telomerase activity was slightly higher in malignant tumors than benign ones with non-significant relation as P value was 0.6.

Conclusions

Calponin showed high diffuse staining with altered distribution in salivary gland tumors, which might give an additional role for this marker in the identification of luminal immuno-modified neoplastic cells. Telomerase is considered as a useful marker in identifying proliferation capacity of salivary gland tumors and is remarkably more detected in malignant salivary gland tumors.

Immunohistochemical study of salivary gland tumors in a tertiary institution in South-South Region of Nigeria

Aim:

The aim of this study was to see the usefulness of immunohistochemistry in diagnosing salivary gland tumors found in a tertiary health institution.

Materials and Methods:

Twenty-six formalin-fixed paraffin embedded salivary gland tumors were accessioned, and 2 μm were sectioned and processed using Streptavidin-Biotin immunoperoxidase method.

Results:

Adenoid cystic carcinoma (ADCC) was positive to alpha-smooth muscle actin (α-SMA) while mucoepidermoid carcinoma (MEC), polymorphous low-grade adenocarcinoma (PLGA), squamous cell carcinoma (SCC) and oncocytic carcinoma (OCC) were all negative to it. MEC, PLGA, ADCC and the only pleomorphic adenoma (PA) were positive to Ki-67 while both SCC and OCC were negative to it. All the tumors except PA were positive to p63.

Conclusion:

It appears that α-SMA may be used to distinguish ADCC from MEC and PLGA, but Ki-67 cannot be used for this purpose. Furthermore, p63 cannot help in the diagnosis of ADCC, MEC or PLGA. It was concluded that immunochemistry can be used as adjunct to routine H and E stain in the diagnosis of the various salivary gland tumors.

Cancer Secretome May Influence BSP and DSP Expression in Human Salivary Gland Cells

One of the biggest challenges in managing head and neck cancers, especially salivary gland cancers, is the identification of secreted biomarkers of the disease that can be evaluated noninvasively. A relevant source of enriched tumor markers could potentially be found in the tumor secretome. Although numerous studies have evaluated secretomes from various cancers, the influence of the cancer secretome derived from salivary gland cancers on the behavior of normal cells has not yet been elucidated. Our data indicate that secretome derived from salivary gland cancer cells can influence the expression of two potential biomarkers of oral cancer-namely, bone sialoprotein (BSP) and dentin sialoprotein (DSP)-in normal salivary gland cells. Using routine immunohistochemistry, immunofluorescence, and immunoblotting techniques, we demonstrate an enrichment of BSP and DSP in human salivary gland (HSG) cancer tissue, unique localizations of BSP and DSP in HSG cancer cells, and enriched expression of BSP and DSP in normal salivary gland cells exposed to a cancer secretome. The secretome domain of the cancer microenvironment could alter signaling cascades responsible for normal cell proliferation, migration, and invasion, thus enhancing cancer cell survival and the potential for cancer progression. The cancer secretome may be critical in maintaining and stimulating "cancer-ness," thus potentially promoting specific hallmarks of metastasis.

Clinical and molecular insights into adenoid cystic carcinoma: Neural crest-like stemness as a target

OBJECTIVES

This review surveys trialed therapies and molecular defects in adenoid cystic carcinoma (ACC), with an emphasis on neural crest-like stemness characteristics of newly discovered cancer stem cells (CSCs) and therapies that may target these CSCs.

DATA SOURCES

Articles available on Pubmed or OVID MEDLINE databases and unpublished data.

REVIEW METHODS

Systematic review of articles pertaining to ACC and neural crest-like stem cells.

RESULTS

Adenoid cystic carcinoma of the salivary gland is a slowly growing but relentless cancer that is prone to nerve invasion and metastases. A lack of understanding of molecular etiology and absence of targetable drivers has limited therapy for patients with ACC to surgery and radiation. Currently, no curative treatments are available for patients with metastatic disease, which highlights the need for effective new therapies. Research in this area has been inhibited by the lack of validated cell lines and a paucity of clinically useful markers. The ACC research environment has recently improved, thanks to the introduction of novel tools, technologies, approaches, and models. Improved understanding of ACC suggests that neural crest-like stemness is a major target in this rare tumor. New cell culture techniques and patient-derived xenografts provide tools for preclinical testing.

CONCLUSION

Preclinical research has not identified effective targets in ACC, as confirmed by the large number of failed clinical trials. New molecular data suggest that drivers of neural crest-like stemness may be required for maintenance of ACC; as such, CSCs are a target for therapy of ACC.

Pleural fluid metastases of myoepithelial carcinoma: A case report and review of the literature

Myoepithelial carcinoma (MECA) is one of the rarest salivary gland neoplasms, which may either arise de novo or develop within a preexisting pleomorphic adenoma or benign myoepithelioma. The tumor occurs mainly in the parotid gland followed by minor salivary glands and other body sites. As a result of their morphologic heterogeneity, they can be confused easily with many tumors. Awareness of their unique cytoarchitectural patterns and immunohistochemical profile is crucial for accurate identification. Herein, we report a rare case of a 51-year-old female patient with MECA of the maxillary sinus that metastasized to the pleural fluid. To the best of our knowledge, this is the first case of pleural fluid involvement by MECA reported in the literature.

Expression of Class II β-Tubulin by Proliferative Myoepithelial Cells in Canine Mammary Mixed Tumors

Benign mammary mixed tumors in dogs resemble human salivary pleomorphic adenomas with regard to their histogenesis, including the occurrence of cartilaginous or bony metaplasia as well as the expression pattern of cytoskeletal proteins in proliferative myoepithelial cells. Recently, a monoclonal antibody specific for class II β-tubulin has been developed. The epitope it recognizes was determined to be the hepta-peptide Glu-Glu-Glu-Glu-Gly-Glu-Asp, which is the common sequence found among the canine, rat, mouse, and human class II β-tubulin-specific regions. We carried out immunohistochemical studies on mammary mixed tumors obtained from three female dogs using this the monoclonal antibody. The antibody to class II β-tubulin reacted intensely with proliferative myoepithelial cells in canine mammary mixed tumors, whereas staining was barely detectable in normal myoepithelial cells surrounding alveoli and alveolar ducts within the tumor and adjacent normal tissue. Proliferative myoepithelial cells also expressed vimentin, but α-smooth muscle actin (αSMA) staining was barely detectable. Immunoblot analysis showed that class II β-tubulin and vimentin were expressed in myoepithelial cell lines prepared from the three mammary mixed tumors. On the other hand, only one cell line, which was negative for αSMA, produced cartilage-specific type II collagen. These results suggest that class II β-tubulin could be a new molecular marker of proliferating myoepithelial cells in canine mammary mixed tumors and that differential expression of cytoskeletal components is associated with cartilaginous metaplasia of proliferative myoepithelial cells in mixed mammary tumors.

Certainty of S100 from Physiology to Pathology

S100 exists in wide variety of tissues and cell types, originally isolated from brain tissue and they are of low molecular weight proteins. S100 is evenly distributed in cytoplasm and also in nucleoplasm and is involved in both intercellular and extracellular functions. S100 protein is generally expressed in normal and also in pathological conditions. In current review, we discuss: a) update nomenclature of the various S100 proteins, b) expression of S100 in oral diseases (different soft tissue tumors, odontogenic cyst and tumor) for diagnostic value and also to know their histogenesis, c) role of S100 and RAGE receptor in oral squamous cell carcinoma.

The unique luminal staining pattern of cytokeratin 5/6 in adenoid cystic carcinoma of the breast may aid in differentiating it from its mimickers

Adenoid cystic carcinoma (AdCC) of the breast is an uncommon but distinct neoplasm composed of a dual cell population polarized around true glandular (luminal) spaces and pseudolumina. The aim of this study was to clarify whether various immunohistochemical markers (CK7, EMA, CD117, p63, calponin, CD10, S100, CK5/6, CK14, vimentin, and type IV collagen) can distinguish between the two cell types in classical AdCC (n = 14) and in collagenous spherulosis (n = 5). The sensitivity and specificity of these 11 markers to distinguish luminal from abluminal cells were evaluated using a curve created by plotting the true-positive rate (sensitivity) against the false-positive rate (1 - specificity) at threshold settings of 0, 10, 50, and 70 %. The most sensitive and specific markers for luminal cells in AdCC were CK7 and EMA; those for abluminal cells were type IV collagen, p63, and vimentin. CD10 and S100 did not act as abluminal markers in AdCC. CK5/6, one of the basal/myoepithelial markers, was expressed more frequently in luminal than in abluminal cells of AdCC. Thus, CK5/6 immunostaining resulted in a reverse expression pattern, analogous to what we recently documented in clear cells in mammary adenomyoepithelioma. In conclusion, compared with myoepithelial/abluminal cells of normal breast or collagenous spherulosis, the neoplastic abluminal cells of classical AdCC are characterized by enhanced vimentin and attenuated CD10 and S100. Furthermore, the luminal cells of AdCC show a unique aberrant staining pattern for CK5/6 that may aid in the differential diagnosis.

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.

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.

Adenoid cystic carcinoma: A review of recent advances, molecular targets, and clinical trials

Background

Adenoid cystic carcinoma (ACC) is a rare tumor of secretory glands. In this study, recent advances in molecular characterization and in therapeutics are reviewed.

Methods

A search of articles in PubMed and of abstracts from national meetings was performed regarding ACC.

Results

Recent genetic analyses found that recurrent chromosome 6:9 translocations in ACC generate an MYB:NFIB gene fusion resulting in overexpression of the MYB oncoprotein. Several other frequent mutations are recently published that may be relevant for drug development. Several trials of targeted drugs are reviewed. Some agents delay tumor progression, but tumor responses remain rare.

Conclusion

ACCs have a characteristic chromosomal translocation, but also frequently pick up additional mutations. Clinical research is limited by the rarity and slow growth of ACC. Several ongoing trials are testing agents that inhibit fibroblast growth factor receptor signaling or other signaling pathways. Novel treatments based on the recently sequenced tumor genome are under development. © 2015 The Authors Head & Neck Published by Wiley Periodicals, Inc. 38: 620–627, 2016

Myoepithelial cell carcinoma of the oral cavity: A case report and review of literature

Myoepithelial carcinoma (MC) is a malignant salivary gland neoplasm whose tumor cells demonstrate cytologic differentiation toward myoepithelial cells and lack ductal or acinar differentiation. It is a relatively rare tumor and many a times remains undiagnosed because of histopathological heterogeneity. It represents about 0.4-0.6% of all salivary gland tumors and 1.2-1.5% of carcinomas. It occurs predominantly in the parotid gland with a mean age of presentation being 55 years (range 14-86) with no sex predilection. MC appears to be a low grade malignancy when arising in a pleomorphic adenoma, but tends to be more aggressive and has a higher metastatic potential when arising de novo. The clinical behavior of MC is variable and there are no pathologic features that correlate with patients' outcome. Most tumors that display marked cytologic atypia, high mitotic activity and necrosis tend to behave aggressively. The current case is of a 42-year-old male with recurrent tumor mass in the mandibular right posterior region. The purpose of this article was to describe the clinicopathological and immunohistochemical features of intraoral MC and to discuss review of literature of this rare tumor.

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.

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.

Squamous/epidermoid differentiation in normal breast and salivary gland tissues and their corresponding tumors originate from p63/K5/14-positive progenitor cells

A small group of tumors of breast and salivary glands contains squamous/epidermoid elements as a constitutive feature (e.g., squamous carcinoma, syringomatous tumors, and mucoepidermoid carcinoma). Other tumors (e.g., pleomorphic adenoma, adenomyoepithelial tumors, and adenoid cystic carcinoma) may show occasionally squamous differentiation. Furthermore, squamous metaplasia may be observed in non-neoplastic breast and salivary tissues. However, the histogenesis of these squamous differentiations is far from being understood. Based on our earlier in situ triple immunofluorescence and quantitative reverse transcription (RT)-PCR experiments for basal keratins K5/14 and p63 as well as for glandular keratins (K7/K8/18), squamous keratins (K10 and K13), and myoepithelial lineage markers (smooth muscle actin, SMA), we here traced the squamous/epidermoid differentiation lineage of 60 tumors of the breast and/or salivary glands, cultured tumor cells of 2 tumors, and of 7 squamous metaplasias of non-neoplastic breast and salivary tissues. Our results indicate that both the neoplastic lesions as well as the non-neoplastic squamous metaplasia contain p63/K5/14+ cells that differentiate toward K10/13+ squamous cells. Thus, cells with squamous/epidermoid differentiation undergo a transition from its original p63/K5/14+ precursor state to K10/13+ squamous lineage state, which can be pictured by triple-immunofluorescence experiments. Given the immunophenotypic similarity of p63/K5/14+ tumor cells to their physiological p63/K5/14+ counterparts in normal breast and salivary duct epithelium, we suggest that these cells provide an important histogenetic key to understanding the pathogenesis of squamous differentiation both in normal breast/salivary gland tissues and their corresponding tumors.

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.

Polymorphous low grade adenocarcinoma has a consistent p63+/p40- immunophenotype that helps distinguish it from adenoid cystic carcinoma and cellular pleomorphic adenoma

Polymorphous low grade adenocarcinoma (PLGA) is a tumor of minor salivary glands that exhibits considerable morphologic overlap with adenoid cystic carcinoma and cellular pleomorphic adenoma, especially in small biopsy specimens. Unlike these other tumor types. PLGAs do not harbor a myoepithelial component, yet their frequent positivity for p63 diminishes the usefulness of this particular myoepithelial marker as a discriminating immunostain. p40 is an antibody that recognizes ΔNp63, a p63 isoform that is more specific for true myoepithelial differentiation. As such, p40 immunostaining could help distinguish PLGAs from adenoid cystic carcinomas and pleomorphic adenomas. In this study, p63 and p40 immunohistochemistry was performed on paraffin embedded, formalin fixed tissue from 11 PLGAs, 101 adenoid cystic carcinomas, and 31 pleomorphic adenomas. All 11 PLGAs (100 %) were positive for p63 but completely negative for p40. Among adenoid cystic carcinomas, 91 of 101 (90 %) were positive for p63 and 90/101 (89 %) were positive for p40. The single discordant p63+/p40- adenoid cystic carcinoma exhibited solid architecture and high grade features not typically seen in PLGA. Among pleomorphic adenomas, 21/31 (68 %) were positive for p63 and 13/31 (42 %) were positive for p40. For the pleomorphic adenomas, the discordant p63+/p40- staining pattern was seen only in the overtly mesenchymal chondromyxoid stroma. The cellular epithelial component of the pleomorphic adenomas demonstrated concordant p63+/p40+ or p63-/p40- immunophenotypes. PLGA consistently exhibits a p63+/p40- immunophenotype that can help distinguish it from adenoid cystic carcinoma and cellular pleomorphic adenoma, tumors that characteristically demonstrate concordant p63 and p40 immunostaining patterns. A p63/p40 immunohistochemical panel can provide a valuable tool for making the distinction between these morphologically similar but clinically divergent entities.

Metastatic renal cell carcinoma, clear cell type, of the parotid gland: a case report, review of literature, and proposed algorithmic approach to salivary gland clear cell neoplasms in fine-needle aspiration biopsies

Renal cell carcinoma (RCC), clear cell type, is a commonly encountered metastatic tumor that can present at unusual anatomic sites many years after the primary tumor resection. Noncutaneous metastasis to the parotid gland is unusual; however, a number of cases of parotid RCC metastasis have been reported. Fine-needle aspiration biopsy (FNAB) is regularly utilized during the evaluation of salivary gland lesions, where it has a high sensitivity, specificity, and accuracy; however, the identification and definitive diagnosis of primary and metastatic clear cell neoplasms is a potential diagnostic pitfall for salivary gland FNAB. Here, we describe a case of RCC, clear cell type, metastatic to the parotid gland that was diagnosed entirely from FNAB cell block material, which is the first such reported case to our knowledge. We review the literature for cases of parotid RCC metastasis and focus on the utility of FNAB for synchronous versus metachronous presentations. Finally, we evaluate the differential diagnosis of clear cell parotid lesions, including ancillary histologic studies, and propose an algorithmic approach to clear cell neoplasms of the salivary gland.

Canalicular adenoma immunoprofile: a case report

OBJECTIVES

To report a case of canalicular adenoma (CA) and discuss the use of immunohistochemistry to better address the diagnosis given some unusual characteristics in this patient.

BACKGROUND

CA is an uncommon benign neoplasm that can develop in minor salivary gland duct tissues throughout the oral cavity. At histology, it shares several features with other salivary tumors. Immunohistochemistry can be useful in the differential diagnosis.

MATERIALS AND METHODS

The clinical presentation consisted in a nodule on the left upper lip of an 85-year-old man. The patient's main complaint was upper denture instability secondary to soft tissue changes. The nodule was excised under local anesthesia and underwent histological and immunohistochemical examination to rule out any malignancy.

RESULTS

Histological findings, cytokeratin positivity and the absence of any reactivity to specific markers of myoepithelial differentiation confirmed the epithelial nature of the lesion.

CONCLUSION

The histological diagnosis of benign salivary tumors such as CA can be confirmed by immunohistochemistry.

Canalicular adenoma--search for the cell of origin: ultrastructural and immunohistochemical analysis of 7 cases and review of the literature

Canalicular adenoma (CA) is a rare, benign epithelial neoplasm of the salivary glands. Historically considered to be a variant of basal cell adenoma, this "monomorphic" adenoma has a distinct clinical, morphologic, and immunohistochemical profile. The putative cell of origin remains a topic of debate. A combination of morphology, immunohistochemistry, and ultrastructural analyses have been employed to determine histogenesis, but the interpretations of these studies have implicated multiple different cell types along the salivary gland duct as the cell of origin. The authors sought to further characterize CA using electron microscopy, immunohistochemistry, and special and immuno-stains on 7 cases. Their morphologic, immunohistochemical, and ultrastructural findings support a cell of origin demonstrating features of both the intercalated duct cells and the striated duct luminal epithelial cells.

Adenoid cystic carcinoma of palate: A case report and review of literature

Adenoid cystic carcinoma is an uncommon, slow growing malignant salivary gland tumor that is characterized by wide local infiltration, perineural spread, propensity to local recurrence and distant metastasis. In this paper, the authors present a case of adenoid cystic carcinoma affecting the palate and involving the maxillary sinus in a 60-year-old male patient along with a brief review of literature.

SOX10 is a novel marker of acinus and intercalated duct differentiation in salivary gland tumors: a clue to the histogenesis for tumor diagnosis

Salivary gland tumors are relatively rare and morphologically diverse and heterogeneous tumors; therefore, histogenesis-based tumor markers are sorely needed to aid in diagnosing and determining the cell type of origin. SRY-related HMG-box 10 (SOX10) protein is a transcription factor known to be crucial in the specification of the neural crest and maintenance of Schwann cells and melanocytes. In addition, positive expression has also been implicated in the major salivary gland. Here, we examined SOX10 expression in various salivary gland tumors to correlate this expression with myoepithelial markers. Overall, 76 malignant and 14 benign tumors were examined. SOX10 expression clearly delineated two distinct subtypes of human salivary gland tumors; acinic cell carcinomas, adenoid cystic carcinomas, epithelial-myoepithelial carcinomas, myoepithelial carcinomas, and pleomorphic adenomas, including the pleomorphic adenoma component of carcinoma, were SOX10 positive, while salivary duct carcinomas, mucoepidermoid carcinomas, an oncocytic carcinoma, Oncocytomas, and Warthin tumors were SOX10 negative. Also, SOX10 was expressed in solid-type or non-specific morphology salivary gland tumors, but was not expressed in poorly differentiated squamous cell carcinomas. In normal human salivary gland tissue, SOX10 expression was specific to the nuclei of acini and both luminal and abluminal cells of intercalated ducts but not in other sites. Moreover, the murine model suggested that SOX10 continued to be expressed from the developmental stage to adulthood in the acinar and both luminal and abluminal intercalated ducts in the major salivary gland. Thus, SOX10 is a novel marker for diagnosing and understanding the histogenesis of salivary gland tumors.

Adenoid cystic carcinoma: clinical and molecular features

The clinical features and common molecular alterations of adenoid cystic carcinoma (ACC) are reviewed in this paper. ACC is an uncommon neoplasm that most frequently arises in salivary glands and related tissue in the head and neck region. ACC has distinct histologic features, with cribriform and tubular growth patterns of basaloid cells displaying a predominantly myoepithelial cellular phenotype. This neoplasm also has uncommon clinical features of rare regional lymph node metastasis and a prolonged but relentlessly progressive clinical course. Clinical outcome in ACC is correlated to histologic grade, which is correlated to the degree of aneuploidy and genetic alterations present in the tumor genomes. Recent studies have identified that the majority of ACC contain alterations of the MYB gene, usually resulting in a fusion gene product with the NFIB gene by a t(6;9) translocation event. The molecular consequences of this alteration are incompletely understood, as are secondary molecular alterations that contribute to the neoplastic phenotype of ACC.

Investigation of myoepithelial cell differentiation into Schwann-like cells in salivary adenoid cystic carcinoma associated with perineural invasion

Perineural invasion (PNI) is common in salivary adenoid cystic carcinoma (SACC). The aim of the present study was to explore the association of the Schwann-like cell differentiation with PNI in SACC. Twenty-eight cases of SACC and 10 cases of acinic cell carcinoma (ACA) were examined for the expression of the Schwann cell markers Leu-7 by immunohistochemical staining. The correlation between Leu-7 expression and PNI was analyzed using κ analysis. Immunofluorescence double-staining and pre-embedding immunogold-silver cytochemistry were used to detect the co-expression and the location of Leu-7 and the myoepithelial cell marker α-smooth muscle actin (α-SMA). PNI was identified in 16 SACCs (57.1%) and 1 ACA (10%) and the overexpression of Leu-7 was detected in 22 SACCs (78.6%) and in none of the ACAs (0%). The differences between PNI and Leu-7 expression in SACC and ACA were significant (P<0.05). A correlation was identified between the expression of Leu-7 and PNI in SACC (κ=0.533, P=0.01). In SACC, Leu-7 and α-SMA were co-expressed in the cytoplasm in the same myoepithelial cells. We suggest that Schwann‑like cell differentiation correlates with PNI in SACC and that the differentiation of myoepithelial into Schwann‑like cells may be one of the mechanisms through which PNI occurs in SACC.

Expression of calponin in periglomerular myofibroblasts of rat kidney with experimental chronic injuries

Our previous research demonstrated that calponin-immunoreactivity was localized in myofibroblasts of the periglomerular region of human kidney specimens obtained at the time of transplantation from organ recipients. In the present study we examined calponin expression in two chronic nephropathy models, puromycin aminonucleoside (PAN) nephropathy and subtotal nephrectomy (SNx), to investigate the role of calponin in chronic renal injury. Male Sprague-Dawley rats were used, and both nephropathy models were established at 1, 2, 4, and 8 weeks after surgery. There were no periglomerular calponin-positive cells in sham, PAN 1 and 2 week, and SNx 1, 2, and 4 week groups. In SNx 8 week and PAN 4 and 8 week groups, only a few glomeruli with periglomerular calponin-reactivity, which covered half or a very small part of the periglomerular space, were observed. All glomeruli with periglomerular calponin-reactivity showed sclerotic changes, especially thickening of parietal epithelial cells (PECs). In conjunction with our previous report, this data represents the first documentation of the expression of calponin in renal myofibroblasts. We suggest that interactions between PECs and calponin-positive myofibroblasts may play a key role in the late stage of glomerulosclerosis.

New variants of epithelial-myoepithelial carcinoma: oncocytic-sebaceous and apocrine

CONTEXT

Recently described variants of epithelial-myoepithelial carcinoma have not been well characterized but raise a distinct set of differential diagnostic considerations than the classic type.

OBJECTIVE

To report a detailed analysis of oncocytic-sebaceous epithelial-myoepithelial carcinoma (OEMCa) and a similar, but novel, variant, apocrine epithelial-myoepithelial carcinoma (ApEMCa).

DESIGN

Clinical, histologic, and immunophenotypic features of 5 OEMCas and 5 ApEMCas were analyzed. Ultrastructural examination was also performed on 3 OEMCa and 1 ApEMCa tumors.

RESULTS

The mean age for OEMCa (74.4 years; range, 58-82 years) was slightly higher than for ApEMCa (61.6; range, 46-79 years). All tumors arose in the parotid glands and demonstrated a multinodular pattern of growth with an average size of 3.3 cm (range, 2.3-6.5 cm). Available follow-up (n = 6; 3 OEMCas, 3 ApEMCas) shows a favorable course (no evidence of disease; mean, 17.4 months). Both were morphologically similar, but only OEMCa had sebaceous elements. Phosphotungstic acid hematoxylin staining, antimitochondrial antibody immunohistochemistry, and ultrastructural examination confirm the abundance of mitochondria in OEMCa but not in ApEMCa. The ductal component in ApEMCa was distinguished from that of OEMCa by apical snouts, intracytoplasmic vacuoles, nuclear pleomorphism, prominent nucleoli, and androgen receptor immunoreactivity.

CONCLUSIONS

Oncocytic-sebaceous epithelial-myoepithelial carcinoma and ApEMCa should be considered in the differential diagnosis of oncocytic/oncocytoid salivary gland tumors. Oncocytic-sebaceous epithelial-myoepithelial carcinoma morphology may reflect a senescent phenotype, similar to other oncocytic lesions. The ductal component of ApEMCa shares some similarities with salivary duct carcinoma and supports the notion that epithelial-myoepithelial carcinoma can serve as the progenitor tumor for hybrid tumors.

Oncocytic mucoepidermoid carcinoma: clinicopathologic description in a series of 12 cases

Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy. Oncocytic MEC (OMEC) has been rarely reported with previous cases suggesting they are largely cystic low-grade neoplasms with a favorable prognosis. The differential diagnosis of OMEC includes numerous oncocytic/"oncocytoid" neoplasms. Some are benign while others are aggressive. Recent evidence suggests that p63 is a reliable marker in the diagnosis of conventional MEC but has not been explored in OMEC. We searched the archives of various institutions for examples of OMEC to re-appraise the grade, and to evaluate p63 immunohistochemistry as a tool to separate OMEC from its potential mimics. A total of 12 cases were identified. There were 6 males and 6 females with an age range of 30 to 79 years. Most occurred in the parotid (9) with 1 each in the sublingual gland, hard palate and neck. They showed minimal cystic content and were infiltrative and solid tumors spanning all grades. All tumors had focal mucin production and were composed almost exclusively of oncocytic cells with 2 cases demonstrating conventional MEC areas. All 6 cases tested showed the majority of oncocytic cells staining with p63 in a diffuse pattern, demonstrating its utility in the diagnosis of OMEC. Of the 6 cases with follow-up information, 1 case had local recurrence 8 years after the initial surgery. Three cases showed skin or bone invasion. None had lymph node/distant metastases. In summary, OMEC behaves as a low-grade tumor, and is diffusely positive for p63, which may aid in its differential diagnosis.

The transcription factor LMO2 is a robust marker of vascular endothelium and vascular neoplasms and selected other entities

The transcription factor LMO2 is involved in vascular and hematopoietic development and hematolymphoid neoplasia. We have demonstrated that LMO2 is expressed nearly ubiquitously in native and neoplastic vasculature, including lymphatics. LMO2 reactivity is otherwise virtually absent in nonhematolymphoid tissues except in breast myoepithelium, prostatic basal cells, and secretory phase endometrial glands. Vasculature is LMO2- in adult and fetal heart, brain of older adults, hepatic sinusoids, and hepatocellular carcinoma. LMO2 is uniformly expressed in benign vascular and lymphatic neoplasms and in most malignant vascular neoplasms with the exception of epithelioid vascular neoplasms of pleura and bone. Among nonvascular neoplasms, LMO2 reactivity is present in giant cell tumor of tendon sheath, juvenile xanthogranuloma, a subset of gastrointestinal stromal tumors, small round blue cell tumors, and myoepithelial-derived neoplasms. The restricted expression pattern, nuclear localization, and crisp staining of LMO2 in paraffin blocks make it an attractive candidate for the diagnostic immunohistochemistry laboratory.

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.

Hierarchical cluster analysis of myoepithelial/basal cell markers in adenoid cystic carcinoma and polymorphous low-grade adenocarcinoma

Distinguishing adenoid cystic carcinoma from polymorphous low-grade adenocarcinoma of the salivary glands is important for their management. We studied the expression of several myoepithelial and basal/stem cell markers (smooth muscle actin, calponin, smooth muscle myosin heavy chain, metallothionein, maspin, and p63) by immunohistochemistry in 23 adenoid cystic carcinoma and 24 polymorphous low-grade adenocarcinoma, to identify the most useful marker or combination of markers that may help their diagnoses. The results were analyzed using hierarchical cluster analysis and chi(2) test for trend. We noted diffuse expression of smooth muscle actin in 20 adenoid cystic carcinoma vs one polymorphous low-grade adenocarcinoma (P<0.0001), calponin in 15 adenoid cystic carcinoma vs one polymorphous low-grade adenocarcinoma (P<0.0001), smooth muscle myosin heavy chain in 15 adenoid cystic carcinoma vs one polymorphous low-grade adenocarcinoma (P=0.001), metallothionein in 22 adenoid cystic carcinoma vs eight polymorphous low-grade adenocarcinoma (P<0.001), maspin in 22 adenoid cystic carcinoma vs 14 polymorphous low-grade adenocarcinoma, and p63 in 21 adenoid cystic carcinoma vs 14 polymorphous low-grade adenocarcinoma. Hierarchical clustering of smooth muscle actin, calponin, smooth muscle myosin heavy chain, and metallothionein was virtually identical (kappa< or =0.0035), suggesting no significant advantage to their use in combination than individually. Diffuse smooth muscle actin expression showed the highest accuracy (91.5%) and positive predictive value (95.2%) for adenoid cystic carcinoma. Thus, diffuse expression of smooth muscle actin, calponin, smooth muscle myosin heavy chain, and metallothionein was highly predictive of adenoid cystic carcinoma, whereas maspin and p63 were frequently expressed in both tumors. In differentiating adenoid cystic carcinoma from polymorphous low-grade adenocarcinoma, smooth muscle actin as a single ancillary test in support of the histological findings, appears to be as efficient as multiple immunohistochemical tests.

Non-sebaceous lymphadenoma of the salivary gland: case report with immunohistochemical investigation

Non-sebaceous lymphadenoma (NSL) is a rare, recently described, benign salivary gland tumor characterized by a dense lymphoid infiltrate and absence of sebaceous differentiation. To our knowledge, only seven previous cases have been reported. In this paper, we describe an additional example of NSL along with an extensive analysis of its keratin (CK) profile. The patient was a 50-year-old woman presenting with a slowly growing painless mass in the right parotid gland. The tumor was encapsulated and measured 3 x 2 x 2 cm. Microscopically, the tumor comprised islands of epithelial cells with centrally located duct-like structures within a dense lymphoid stroma. Immunohistochemically, the tumor regularly expressed CKs 7, 8/18, and 19, which are typical for columnar differentiation and CKs 17 and 5/6, which are most typically expressed in basal cells of complex epithelia. CK14 was only expressed in rare scattered cells and eventually in groups of cells. The expression of CK10/13, which correlates with squamous differentiation, was negative. Additionally, immunostaining for smooth muscle actin, vimentin, and S-100 was also performed. The immunohistochemical findings in the neoplastic epithelial component of our case suggest a differentiation of "intercalated duct phenotype" without myoepithelial cell participation.

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.

Application of α-smooth muscle actin and c-kit in the differential diagnosis of adenoid cystic carcinoma from polymorphous low-grade adenocarcinoma

The expression of vimentin, alpha-smooth muscle actin (alpha-SMA) and c-kit in adenoid cystic carcinomas (AdCCs) and polymorphous low-grade adenocarcinomas (PLGAs) was investigated immunohistochemically to evaluate the application of these markers to distinguish AdCCs from PLGAs when the histological features are equivocal. Tissue specimens of AdCCs and of PLGAs, formalin-fixed and paraffin-embedded were retrospectively studied using vimentin, alpha-SMA and c-kit. Positive staining for alpha-SMA was identified in all AdCCs and 25% of PLGAs. The immunoreactivity of c-kit in all positive cases of AdCCs (83%) and PLGAs (41%) was more than 50% and less than 50% of tumor cells respectively. The expression pattern for both alpha-SMA and c-kit, in tubular structures of AdCCs was different of that seen in the same structures in PLGAs. The results of this study support the potential application of alpha-SMA and c-kit as an adjunctive aid in the differential diagnosis of AdCCs from PLGAs.

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.

A salivary malignant myoepithelioma in a dog

Salivary tumours are uncommon in domestic animals and there are no known previous confirmed reports of salivary tumours of myoepithelial origin in dogs. A 12-year-old female mixed breed dog was presented with a lobulated mass, composed of white-yellowish tissues, extending from soft palate to epiglottis. Histological examination revealed a neoplastic lesion consisting of a dense population of cells showing moderate pleomorphism, with pale cytoplasm and large oval nuclei, arranged in solid lobules. Mitotic activity was very high. Tumoral cells were negative for both periodic acid-Schiff reaction and Alcian blue stain and displayed strong immunohistochemical reactivity for pan-cytokeratin, muscle specific actin and myosin and focal positivity for cytokeratin 14. On the basis of the morphological, histochemical and immunohistochemical findings a diagnosis of malignant tumour of myoepithelial origin (malignant myoepithelioma) was made.

Selective Immunohistochemical Comparison of Polymorphous Low-Grade Adenocarcinoma and Adenoid Cystic Carcinoma

PURPOSE

Polymorphous low-grade adenocarcinoma (PLGA) is a salivary gland malignancy characterized by indolent growth and a low rate of metastasis. PLGA shares histological features with adenoid cystic carcinoma (ACC), including infiltrating solid and cribriform patterns, presence of cystic spaces, and neurotropism. The degree of polymorphism of PLGA presents diagnostic challenges, particularly in small biopsy specimens. Immunohistochemical reactions to differentiate PLGA from the more aggressive ACC would be extremely valuable but controversy exists in the current literature regarding their utility. This study examines the potential use of c-kit, Ki-67, smooth muscle actin (SMA), and muscle-specific actin (MSA) as ancillary markers for distinguishing PLGA from ACC.

PATIENTS AND METHODS

Medical records of 20 cases of PLGA treated at the Massachusetts General Hospital were reviewed. Patient demographic data and tumor-specific information were elicited. Formalin-fixed paraffin-embedded sections from 10 of these cases and 12 comparison cases of ACC were accessed. The histologic diagnoses were confirmed and immunohistochemical staining using antibodies to c-kit, Ki-67, SMA, and MSA was employed to determine differences in staining.

RESULTS

PLGA showed a significantly weaker immunohistochemical expression of c-kit compared with ACC (P = < .001). Ki-67, correlating with proliferative behavior, was more weakly expressed in PLGA (P = .091). The exuberant myoepithelial component of ACC resulted in stronger staining with SMA and MSA (P = .047; P = .065, respectively).

CONCLUSIONS

Statistically significant immunohistochemical staining patterns using c-kit and SMA in this study support their potential use as markers to differentiate PLGA from ACC in cases where the diagnosis can be challenging.

Immunohistochemical expression of p63 in pleomorphic adenomas and carcinomas ex-pleomorphic adenomas of salivary glands

Alteration of the p63 protein expression has been associated with several human cancers including salivary gland tumors. We sought to assess the p63 expression in pleomorphic adenomas (PA) and carcinoma ex-pleomorphic adenomas (Ca ex-PA), since this protein has been related to myoepithelial phenotype and the biological behavior of cancer. Ten samples of PA and ten of Ca ex-PA were submitted to immunohistochemistry using a monoclonal anti-p63 antibody, clone 4A4. p63 was regularly expressed in myoepithelial cells' nuclei of the normal glandular parenchyma and in PA, but it was completely absent in five out of the ten samples of Ca ex-PA. (P < 0.05 by Fisher's exact test). Apparently, only those cases depicting some myoepithelial differentiation were positive. Our data suggest that loss of myoepithelial differentiation is important in the evolution of Ca ex-PA, and corroborate the hypothesis that p63 antigen may be a useful marker of myoepithelial cells in salivary glands neoplasms.

Differential expression of p63 isotypes (DeltaN and TA) in salivary gland neoplasms: biological and diagnostic implications

To determine the association between the expression of p63 gene isoforms (TA and DeltaN) and salivary gland tumorigenesis, we performed reverse transcription-polymerase chain reaction analysis of these markers in 71 benign and malignant salivary gland neoplasms. The results were correlated with the expression of Notch ligand JAG1 gene and the clinicopathologic features and the full-length p63 protein expression by immunohistochemistry. Both p63 isoforms were either negative or weakly expressed in normal salivary gland tissues. TAp63 was highly expressed in most benign tumors and was either negative or weakly positive in most carcinomas. Conversely, DeltaNp63 was negative or faintly positive in most benign neoplasms and was highly expressed in adenoid cystic, mucoepidermoid, and myoepithelial carcinomas. Immunohistochemical analysis using anti-full-length p63 protein showed ubiquitous nuclear staining in basal and myoepithelial cells in both benign and malignant neoplasms. JAG1 was expressed in most benign and malignant tumors and did not correlate with p63 isoforms expression. We conclude that (1) p63 isoforms are differentially expressed in most benign and malignant tumors and may play distinct biological roles in certain salivary gland neoplasms; (2) p63 immunostaining do not correlate with the isoforms expression; and (3) isoform-specific antibodies are required for better cellular localization and biological correlations.

Myoepitheliale Tumoren der Haut und des Weichgewebes

Myoepithelial neoplasms of skin and soft tissues comprise cutaneous mixed tumor (chondroid syringoma), mixed tumor of subcutaneous and deep soft tissues, myoepithelioma and rare malignant myoepithelioma (myoepithelial carcinoma). Myoepithelial tumors of skin and soft tissues are characterized by an extreme clinicopathological heterogeneity as in other anatomic locations. The neoplasms arise in childhood as well as in adults and are composed of epithelioid, histiocytoid, spindled, plasmocytoid and/or clear tumour cells in varying combinations, and are set in a myxoid or hyalinised intercellular matrix. Immunohistochemically, neoplastic cells stain positively for epithelial markers (pancytokeratin and/or epithelial membrane antigen), and often for S 100 protein. More rarely muscle actin, glial fibrillary acid protein, calponin, and p63 are expressed, whereas desmin is usually negative. The presence of at least moderate cytological atypia is associated with a significant risk for aggressive behavior and propensity for metastasis.