Immunohistochemical expression of cytokeratins 7 and 20 in malignant salivary gland tumors

Nasopharyngeal mucoepidermoid carcinoma with mastermind-like transcriptional coactivator 2 translocation: A case report and comprehensive literature review of a rare entity

Mucoepidermoid carcinoma is one of the most common malignant tumors in salivary glands and is usually associated with mastermind-like transcriptional coactivator 2 (MAML2) rearrangement. Primary nasopharyngeal mucoepidermoid carcinoma is extremely rare, and MAML2 status was reported in only two studies. Herein, we present a 70-year-old male patient with incidentally found nasopharyngeal mucoepidermoid carcinoma. MAML2 translocation was detected by fluorescence in situ hybridization test. Additionally, we conducted a comprehensive literature review and summarized the clinicopathological features of this rare condition. Nasopharyngeal mucoepidermoid carcinoma shows a similar mean age at diagnosis and gender ratio to those of mucoepidermoid carcinoma in salivary glands. More than half of the patients exhibit high histologic grade at the time of diagnosis. As MAML2 status is unreported in almost all published cases, further studies are needed to explore the incidence and prognostic value of MAML2 rearrangement in nasopharyngeal mucoepidermoid carcinoma.

Unusual case of extramammary Paget disease of the oral mucosa: A case report and literature review

Paget disease is an intraepithelial neoplastic proliferation, commonly occurring in the breast and apocrine-rich areas, often associated with an underlying internal malignancy. Extramammary Paget disease (EMPD) of the oral cavity is exceedingly rare, with only eight reported cases, four of which were associated with an underlying internal malignancy. Here, we report a case of oral EMPD involving the buccal mucosa and gingiva of an 81-year-old male with no known underlying internal malignancy. The Paget cells were positive for CK7, CK20, CAM5.2, and androgen receptor, but negative for SOX10 and p63. The immunophenotype, association with internal malignancies, and treatment approaches for oral EMPD are reviewed.

Establishment and molecular characterization of HCB-541, a novel and aggressive human cutaneous squamous cell carcinoma cell line

Cutaneous squamous cell carcinoma (cSCC) is a common type of skin cancer that can result in significant morbidity, although it is usually well-managed and rarely metastasizes. However, the lack of commercially available cSCC cell lines hinders our understanding of this disease. This study aims to establish and characterize a new metastatic cSCC cell line derived from a Brazilian patient. A tumor biopsy was taken from a metastatic cSCC patient, immortalized, and named HCB-541 after several passages. The cytokeratin expression profile, karyotypic alterations, mutational analysis, mRNA and protein differential expression, tumorigenic capacity in xenograft models, and drug sensitivity were analyzed. The HCB-541 cell line showed a doubling time between 20 and 30 h and high tumorigenic capacity in the xenograft mouse model. The HCB-541 cell line showed hypodiploid and hypotetraploidy populations. We found pathogenic mutations in TP53 p.(Arg248Leu), HRAS (Gln61His) and TERT promoter (C228T) and high-level microsatellite instability (MSI-H) in both tumor and cell line. We observed 37 cancer-related genes differentially expressed when compared with HACAT control cells. The HCB-541 cells exhibited high phosphorylated levels of EGFR, AXL, Tie, FGFR, and ROR2, and high sensitivity to cisplatin, carboplatin, and EGFR inhibitors. Our study successfully established HCB-541, a new cSCC cell line that could be useful as a valuable biological model for understanding the biology and therapy of metastatic skin cancer.

Primary Epithelioid Angiosarcoma of the Submandibular Gland-A Case Report with Histology-Cytology Correlation and Comprehensive Molecular Analysis

BACKGROUND

Angiosarcoma is a sarcoma that occurs in a range of tissue types, and only rarely in the salivary glands, showing a predilection for the parotid glands of older patients. Preoperative diagnosis may be challenging, especially on cytology, with significant morphological overlap with high-grade primary salivary gland carcinomas. The molecular alterations of this rare salivary gland neoplasm are also not well-characterized.

METHODS AND RESULTS

We present a case of right submandibular gland swelling in a 73-year-old male. On fine needle aspiration, including immunohistochemical stains on cell block, the tumor was initially diagnosed as poorly differentiated carcinoma. Resection of the submandibular gland revealed epithelioid angiosarcoma. We performed molecular work-up of the tumor, utilizing targeted next-generation sequencing, DNA methylation profiling and fluorescence in-situ hybridization. Histopathologic assessment revealed an infiltrative tumor comprising solid sheets of epithelioid cells. The tumor cells formed haphazardly anastomosing vascular channels with intracytoplasmic lumina containing red blood cells. On immunohistochemistry, the tumor cells were positive for CD31, CD34 and ERG. Approximately 40% of the tumor cells showed nuclear expression of GATA3. A pathogenic TP53 R267W mutation was detected on next-generation sequencing. DNA methylation analysis did not cluster the tumor with any known sarcoma type. Copy number analysis showed possible MYC amplification and CDKN2A losses, although only the latter was confirmed on fluorescence in-situ hybridization.

CONCLUSION

Epithelioid angiosarcoma is an important differential diagnosis to high-grade salivary gland carcinoma. In particular, GATA3 expression may be encountered in both angiosarcoma and high-grade salivary gland carcinomas and cause diagnostic confusion. Identification of TP53 mutations and CDKN2A losses suggest shared oncogenic pathways with soft tissue angiosarcomas, and should be further investigated.

Current Developments in Diagnosis of Salivary Gland Tumors: From Structure to Artificial Intelligence

Salivary glands tumors are uncommon neoplasms with variable incidence, heterogenous histologies and unpredictable biological behaviour. Most tumors are located in the parotid gland. Benign salivary tumors represent 54-79% of cases and pleomorphic adenoma is frequently diagnosed in this group. Salivary glands malignant tumors that are more commonly diagnosed are adenoid cystic carcinomas and mucoepidermoid carcinomas. Because of their diversity and overlapping features, these tumors require complex methods of evaluation. Diagnostic procedures include imaging techniques combined with clinical examination, fine needle aspiration and histopathological investigation of the excised specimens. This narrative review describes the advances in the diagnosis methods of these unusual tumors-from histomorphology to artificial intelligence algorithms.

Clinicopathological practice in the differential diagnosis of mucoepidermoid carcinoma from neoplasms with mucinous component

Background

The differential diagnosis of mucoepidermoid carcinoma (MEC) from neoplasm undergoing mucinous features brings more pitfalls to pathologists. Combining specific MAML2 gene rearrangement and histological characteristics may be the solution.

Methods

Twenty-five tumors with mucinous components were selected for differential diagnosis of MEC. All the cases were detected for MAML2 gene rearrangement. The cases diagnosed as MEC were classified into four variants: classic, oncocytic, Warthin-like, and nonclassified, and they were graded using the Brandwein system. The histological characteristics of non-MECs were summarized for differential diagnosis. Univariate survival analysis was performed on MECs.

Results

There were 16 MECs; 62.5% were MAML2 rearranged. For the low-, intermediate-, and high-grade MECs, the rate of rearrangement was 83.3%, 100%, and 28.6%, respectively. Both the oncocytic and Warthin-like MECs were MAML2 rearranged. For the classic and nonclassified MECs without MAML2 rearrangement, non-keratinized squamoid cells and distinctive mucinous cells were essential diagnostic criteria. On survival analysis, all the disease progression occurred in high-grade MECs (p = 0.038). Nine cases were diagnosed as non-MECs: pleomorphic adenoma with mucinous metaplasia showed no ex-capsular involvement; metaplastic Warthin tumor appeared with overt keratinization and residual oncocytic bilayered epithelium; mix squamous cell and glandular papilloma showed an endobronchial papillary growing pattern; adenosquamous carcinoma was accompanied by squamous carcinoma in situ of the overlying mucosa. All the non-MECs were negative for MAML2 rearrangement.

Conclusion

The application of combining MAML2 rearrangement and histological characteristics is helpful in the differential diagnosis between MEC and other tumors with mucinous components.

Immunohistochemical Profile of Polymorphous Adenocarcinoma of Minor Salivary Gland: A Systematic Review and Meta-Analysis

Polymorphous adenocarcinoma (PAC) is a rare variant of minor salivary gland tumors. Because of its architectural diversity, histological diagnosis of PAC can be difficult especially for small biopsies, and immunohistochemistry is of great help in differentiating it from its histologic mimics. The aim of this study is to conduct a systematic literature review to identify reliable immunohistochemical markers for PAC. We conducted an electronic literature search of the MEDLINE, ScienceDirect, SpringerLink, and Wiley Online Library databases, covering the literature published in the period between 1988 and 2021. The eligibility criteria included case reports and retrospective studies of PAC cases with details of immunohistochemical markers. Following the search and selection process, 32 studies with 409 cases were included in this systematic review. Overall, > 90% positivity was observed for pan-cytokeratin (CK) (97.3%), CK7 (96.8%), CK7/8 (97.4%), E-cadherin (90.0%), Vimentin (92.5%), S100 (97.0%), p63 (91.7%), and SOX10 (100%), while little to no positivity was observed for CK20 (0.0%), p40 (0.0%), and GFAP (5.0%). The average MIB-1 labeling index was 3.78%. The results of this systematic review indicate that CK7+/CK20-, p63+/p40-, S100+, Vimentin+, and GFAP- immunophenotype have diagnostic value for PAC. In addition, the use of S100, MSA, p40, and c-Kit provide additional layers of information helpful to differentiate PAC from adenoid cystic carcinoma, one of challenging differential diagnoses.

An immunohistochemical expression of CK5/6, CK7, and CK20 on cell blocks in metastatic cervical lymphadenopathy

Background

The neck is a common site of both primary and secondary malignancies. Many tumors from the head and neck (oral cavity, larynx, and pharynx), lung, and gastrointestinal tract metastasize to cervical lymph nodes. At most times, tumors are diagnosed by morphology, sometimes it is difficult to diagnose an unknown primary presenting as metastatic lymphadenopathy solely on the basis of morphology. Specific histological cell types can be confirmed by the use of immunohistochemistry.

Aim

The present study evaluated the utility of cell block over fine-needle aspiration cytology (FNAC) and immunohistochemical expression of CK5/6, CK7, and CK20 in metastatic cervical lymphadenopathy.

Methods:

This prospective study design was used on a total of 50 cases. FNAC smears and cell blocks were made in all the cases. All the cell blocks were compared with FNAC findings and further subjected to immunohistochemical (IHC) analysis. The necessary statistical analysis was done.

Results and Conclusion

Our study showed that the combined use of the cell block technique and FNAC was more useful and sensitive in diagnosing the metastatic cervical lymph nodes and the accuracy can be further improved by the use of IHC on the cell blocks. The combined use of CK5/6, CK7, and CK20 in metastatic cervical lymphadenopathy is helpful in diagnosing squamous cell carcinoma and adenocarcinoma with known/unknown primary sites.

Cytokeratins (CK7 and CK20) Genes Expression Association with Clinicopathological Indices in Oral Squamous Cell Carcinoma and Dysplastic Oral Epithelium

Background

High prevalence of oral squamous cell carcinoma (OSCC) demands the additional novel biological markers. Due to the established roles of cytokeratin in the prognosis of metastasis evaluation the relation of expression of both CK7 and CK20 in OSCC compared to the dysplastic oral epithelium biopsies with clinicopathological factors were investigated.

Methods

We examined the coordinate mRNA expression of cytokeratin 7 (CK7) and cytokeratin 20 (CK20) using quantitative reverse transcription polymerase chain reaction (qRT-PCR) in 110 biopsies of oral squamous epithelium samples including 72 tumoral and 38 dysplastic biopsies. We also collected demographic and pathological data including tumor stage and grade from our patients.

Results

There was a significant difference in CK7 and CK20 gene expression between OSCC and dysplastic samples (p< 0.001). Further, their mean expression in OSCC samples was significantly higher compared to dysplastic samples. Relative mRNA levels of CK7 and CK20 showed that their mean expression in OSCC grade I was significantly lower than other grades (p< 0.01). The relationship between CK7 and CK20 mRNA expression and age or gender was not significant (p> 0.05). Samples in the advanced stage of disease had significantly higher CK7 and CK20 expression compared to early-stage samples of OSCC specimens (p= 0.001).

Conclusion

We found an increase in CK7 and CK20 mRNA levels in grade III OSCC samples compared to other grades. This finding suggests a potential role for CK7 and CK20 in oral mucosal carcinogenesis and OSCC prognosis.

[Immunohistochemical diagnosis of necrotizing sialometaplasia]

The article presents a clinical case of an immunohistochemical study of a rare disease: necrotizing sialometaplasia in the hard palate. Due to the complexity of the differential diagnosis between necrotizing sialometaplasia and squamous cell carcinoma, an immunohistochemical method was used with antibodies to proteins Ki-67, P53, P63 and cytokeratins-7 and Immunohistochemical study established low proliferative activity of glandular cells in excretory ducts and metaplastic squamous epithelium for Ki-67 protein, significant expression of protein P63 was detected both in the ductal epithelium nuclei and in metaplastic areas and expression of the mutant protein P53 was approximately absent. Marked expression of cytokeratin-7 in the ducts cells and weak expression in necrotic acini of the glands and metaplastic epithelium was noted. It was shown that cytokeratin-15 homogeneously stains the peripheral zone of metaplastic epithelium, which is characteristic of a benign lesion. Thus, the panel of antibodies to proteins Ki-67, P53 and cytokeratins-7 and 15 allows to verify necrotizing sialometaplasia.

Metallothionein Expression and its Influence on the In Vitro Biological Behavior of Mucoepidermoid Carcinoma

Mucoepidermoid carcinoma (MEC) is the most common tumor in the salivary glands, often presenting with recurrence and metastasis due to its high invasive capacity. Metallothionein (MT), a zinc storage protein that supplies this element for protease activity, is probably related to mucoepidermoid carcinoma behavior. This prompted us to characterize a cell line derived from mucoepidermoid carcinoma and to correlate metallothionein expression with transforming growth factor-α (TGF-α), tumor necrosis factor-α (TNF-α) and matrix metalloproteinases (MMPs). Transcriptomic analysis and cytogenetic assays were performed to detect the expression of genes of interest and cellular chromosomal alterations, respectively. MEC cells with a depleted metallothionein 2A (MT2A) gene were subjected to Western blot to correlate metallothionein expression with growth factors and MMPs. Additionally, cells with depleted MT were subjected to migration and invasion assays. The transcriptomic study revealed reads mapped to cytokeratins 19 and AE1/AE3, α-smooth muscle actin, vimentin, and fibronectin. Cytogenetic evaluation demonstrated structural and numerical alterations, including the translocation t(11;19)(q21;p13), characteristic of MEC. Metallothionein depletion was correlated with the decreased expression of TGF-α and MMP-9, while TNF-α protein levels were augmented. Migration and invasion activity were diminished after metallothionein silencing. Our findings suggest an important role of MT in MEC invasion, through the regulation of proteins involved in this process.

The Emerging Role of Cytoskeletal Proteins as Reliable Biomarkers

Cytoskeletal proteins are essential building blocks of cells. More than 100 cytoskeletal and cytoskeleton-associated proteins are known and for some, their function and regulation are understood in great detail. Apart from cell shape and support, they facilitate many processes such as intracellular signaling and transport, and cancer related processes such as proliferation, migration, and invasion. During the last decade, comparative proteomic studies have identified cytoskeletal proteins as in vitro markers for tumor progression and metastasis. Here, these results are summarized and a number of unrelated studies are highlighted, identifying the same cytoskeletal proteins as potential biomarkers. These findings might indicate that the abundance of these potential markers of tumor progression is associated with the biological outcome and are independent of the cancer origin. This correlates well with recently published results from the Cancer Genome Atlas, indicating that cancers show remarkable similarities in their analyzed molecular information, independent of their organ of origin. It is postulated that the quantification of cytoskeletal proteins in healthy tissues, tumors, in adjacent tissues, and in stroma, is a great source of molecular information, which might not only be used to classify tumors, but more importantly to predict patients' outcome or even best treatment choices.

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.

Salivary duct carcinoma of the supraglottis with a distinct presentation: A case report and literature review

RATIONALE

Salivary duct carcinoma (SDC) is a rare and aggressive subtype of salivary gland carcinoma that histologically resembles in situ and invasive ductal carcinoma of the breast. We present the first case of advanced SDC of the minor salivary gland arising from the supraglottis and review the literature on the clinicopathologic characteristics and prognosis of SDC.

PATIENT CONCERNS

A 59-year-old male patient with progressive difficulty in swallowing and a muffled voice for 2 months.

DIAGNOSES

The patient was diagnosed with SDC arising from the supraglottis with extensive tumor invasion into the subsites of the larynx and pharynx.

INTERVENTIONS

Due to impending airway obstruction, the patient underwent CO2 laser debulking surgery. In addition to local disease, lymph node and distant metastases were also noted at diagnosis and concurrent chemoradiation therapy was arranged.

OUTCOMES

Laryngeal function was preserved and tracheostomy was avoided. The patient has survived for >1 year after the initial diagnosis.

LESSONS

SDC is a rare and aggressive subtype of salivary gland carcinoma that histologically resembles in situ and invasive ductal carcinoma of the breast. Here we presented the first case of advanced SDC of the minor salivary gland arising from the supraglottis that was treated with CO2 laser debulking surgery followed by concurrent chemoradiation therapy. Due to their rarity, further studies are required to establish the most effective treatment protocol for advanced SDC.

Intraoral Pigmented Low-Grade Adenocarcinoma, Not Otherwise Specified: Case Report and Immunohistochemical Study

Salivary adenocarcinoma, not otherwise specified (AdCaNOS) is a rare malignant tumor with potential diagnostic challenge, which mainly affects the parotid glands; however, the minor salivary glands can also be involved by AdCaNOS. This paper reports a case of a 45-year-old Afro-descendant woman complaining of a slow-growing mass with 6 months of evolution in the left superior vestibular fornix. Microscopic examination revealed an infiltrative epithelial neoplasm composed of predominantly solid growth pattern, arranged in a lobular configuration, admixed with glandular or ductal structures. Perineural invasion was evident. The tumor cells were polygonal or oval showing focally mild nuclear pleomorphism, and eosinophilic or clear cytoplasm. Notably, some areas exhibited intracytoplasmic pigment granules mainly in non-luminal cells, as well as sebaceous-like cells, discrete hyaline material deposition and foci of infiltration of residual salivary gland parenchyma. Tumor cells were negative for PAS, mucicarmine and Alcian blue stains. By immunohistochemistry, the tumor cells were diffuse and strongly positive for pan-cytokeratin (CK) AE1/AE3, 34betaE12 CK, vimentin, p63 and S100. CK7 and EMA strongly highlighted the ductal structures. Solid areas also showed diffuse and moderate expression of CD56. Podoplanin (D2-40), GFAP and Calponin, followed by DOG-1, were focally positive; whereas CK20, α-SMA, h-Caldesmon, CD57, ERBB2/HER2 and p53 were negative. Ki-67 was < 2%. Consecutive serial tissue sections using CD57 confirmed the perineural invasion. Positivity for HMB-45 and MART-1/Melan-A, as well as Fontana-Masson stain (and potassium permanganate bleaching-sensitive), identified the pigment granules as melanin. To the best of our knowledge, this is the first case of intraoral low-grade AdCaNOS with intracytoplasmic melanin granules.

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.

Salivary duct carcinoma in the mandibular anterior region: The role of immunohistochemical markers in its definitive diagnosis

Salivary duct carcinoma (SDC) is a high-grade adenocarcinoma arising from the ductal epithelium of salivary glands which rarely involves the minor salivary glands. The varied histological presentation in the minor salivary gland tumors makes them the most heterogeneous group of neoplasms, making the diagnosis a challenge. This report highlights the importance of immunohistochemical markers in the definitive diagnosis of SDC.

[A bilateral epithelial myoepithelial carcinoma of the parotid gland]

We report the case of a 52-year-old man, who was admitted in the department of otorhinolaryngology for a mass of the right parotid gland. The radiological and clinical hypothesis was a squamous cell carcinoma. Histopathological examination revealed a biphasic proliferation composed of epithelial cells arranged in a tubular pattern stained with cytokeratins 5-6 and 7 and EMA surrounded by clear myoepithelial cells stained with smooth muscle actin and p63. Ki-67 labeling index was low. The diagnosis of epithelial myoepithelial carcinoma was proposed. One year after, the patient noticed a centimetric mass of the left parotid gland. The radiological hypothesis was the presence of an intraparotidian lymph node. Histopathological examination showed a second epithelial myoepithelial carcinoma. This is an uncommon neoplasm comprising approximately 1% of all salivary gland tumours, affecting mainly the parotid gland. It is occurring preferably in patients older than 60years old. This is a low-grade malignant tumour with tendency to local recurrence and lymph node metastatic potential. We describe an exceptional bilateral epithelial myoepithelial carcinoma of the parotid gland.

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.

Salivary duct carcinoma of the parotid gland: A case report and review of the literature

Salivary duct carcinoma (SDC) is a rare and aggressive parotid malignancy that most commonly affects males in the fifth and sixth decades of life. Histopathology specimens obtained from SDC patients demonstrate a resemblance to ductal carcinoma of the breast. Therefore, to distinguish SDC from breast ductal carcinoma, several immunohistochemical markers exist that may enable surgeons to make an accurate diagnosis. In this study, the case of a 54-year-old male with salivary duct carcinoma of the right parotid gland is presented. The results of the present case study revealed that the SDC sample was positive for the expression of human epidermal growth factor 2 (Her-2), cytokeratin (CK) 8/CK 18, p63, high molecular weight CK and calponin, and negative for expression of the estrogen receptor and progesterone receptor. Based on the result, an ipsilateral selective neck dissection followed by adjuvant post-operative radiation therapy was suitable at the primary treatment stage. At one year of follow-up, the patient was alive and free of recurrence. In advanced cases of SDC, treatment with anti-HER-2 monoclonal antibodies, such as trastuzumab, is recommended.

Recent advances in the diagnostic pathology of salivary carcinomas

This review concentrates on the most important developments since the WHO classification of 2005. In particular, the identification of specific translocations is revolutionising the way salivary tumours are considered and will have a major impact on future diagnostic practice. This is true so far in four malignancies: mammary analogue secretory, mucoepidermoid, adenoid cystic and hyalinising clear cell carcinomas. In each, the gene rearrangement is found in 80 % or more of cases. Two 2014 publications have added further possible candidates with molecular abnormalities to the list (cribriform adenocarcinoma of the tongue and minor salivary glands and epithelial-myoepithelial carcinoma), but these findings have yet to be confirmed by other investigators. The advances in molecular pathology have also allowed re-evaluation of the morphology; for example, it is now realised that the histological spectrum of hyalinising clear cell carcinoma includes intracellular mucin in over half of cases, as well as tumours with only scanty clear cells. In a separate development, it is now proposed that salivary duct carcinoma can be subdivided along molecular lines, in ways analogous to breast cancer, suggesting new therapeutic prospects in an otherwise highly aggressive malignancy.

Oral cytokeratins in health and disease

The dynamics of oral mucosa is known by its inherent defensive nature. Certain areas demand tough shield when subjected to mechanical insults. This is met by structural scaffolding material referred as cytoskeleton comprised of intracellular protein filaments called cytokeratins in the surface squames of oral epithelia. They also equally contribute towards the architecture of odontogenic apparatus and salivary gland. Differentiation of epithelial cells within stratified epithelia regulates the expression of specific keratin gene. Any mutation in, or autoantibodies to keratins, desmosomal and cornified envelope proteins is translated into genetic and acquired human disorders. Sound knowledge of structural proteins, their expression, distribution and function plays a vital role in acquainting with these disorders and their application as differentiation markers. Thus, they form an integral aid in diagnostic pathology and may be instrumental in the future interventions by gene therapy. This review focuses on basics to current updates on oral cytokeratins with an emphasis on the genetic and acquired disorders of cytokeratins with oral implications.

Salivary duct carcinoma: new developments--morphological variants including pure in situ high grade lesions; proposed molecular classification

Salivary duct carcinoma (SDC) is an aggressive primary salivary malignancy which microscopically resembles high-grade ductal carcinoma of the breast, with both in situ and invasive patterns. It is typically found in older men, most often in the parotid. It can arise de novo or as the malignant component of carcinoma ex pleomorphic adenoma. SDC is generally a hematoxylin and eosin stain-based diagnosis, with special stains and immunohistochemistry acting mainly in a confirmatory role. Other than epithelial markers, SDC expresses androgen receptors in most cases, with true HER2 positivity seen in about 15 %. Based on these data and analogous to similar schemes in the breast, it is suggested that SDCs can be classified into three main groups: luminal androgen receptor positive, HER2+ and basal phenotype. This may form the basis for prognostic information and new therapeutic possibilities. In addition to the usual type of SDC, a few less common morphological variants have been reported: papillary, micropapillary, mucin-rich, sarcomatoid and oncocytic, as well as pure in situ cases.

Contribution of proteomics to the study of the role of cytokeratins in disease and physiopathology

Cytokeratins (CKs), the most abundant group of cytoskeletal intermediate filaments, and proteomics are strongly connected. On the one hand, proteomics has been extremely useful to uncover new features and functions of CKs, on the other, the highly abundant CKs serve as an exceptional tool to test new technological developments in proteomics. As a result, proteomics has contributed to finding valuable associations of CKs with diseases as diverse as cancer, cystic fibrosis, steatohepatitis, viral and bacterial infection, keratoconus, vitreoretinopathy, preeclampsia or the chronic fatigue syndrome, as well as to characterizing their participation in a number of physiopathological processes, including drug resistance, response to toxicants, inflammation, stem cell differentiation, embryo development, and tissue repair. In some cases, like in cystic fibrosis, CKs have been described as potential therapeutic targets. The development of a specific field of proteomics where CKs become the main subject of research aims and hypotheses is suggested.

An improved approach to diagnosing and treating conjunctival mucoepidermoid carcinoma

The current case of conjunctival mucoepidermoid carcinoma offers features that expand the biologic spectrum afforded by this tumor. More focused strategies should be developed for its earlier histopathologic diagnosis and improved management (historical recurrence rate of 85%). A 63-year-old woman with a history of rheumatoid arthritis and idiopathic sclerosing cholangitis developed scleral thinning, anterior chamber cells and flare, and uveal prolapse. Biopsies of the epibulbar lesion were initially misinterpreted as a squamous cell carcinoma but on review harbored CK7-positive cells and contained rare goblet cells brought out with Alcian blue and mucicarmine staining. Intraocular extension exhibited micro-and macrocysts with minimal goblet cells. Focal CK7 immunopositivity in any epibulbar squamous dysplasia or in invasive carcinoma should lead to suspicion of a mucoepidermoid carcinoma. Behaviorally aggressive or rapidly recurrent epithelial squamous tumors with "inflammatory" features or unusual clinical characteristics should be initially stained at multiple levels for the detection of parsimonious mucus secretion. Surgical options include wide excision and partial sclerectomy with cryotherapy for superficial invasion and/or interferon therapy. Results with radiotherapy and cryotherapy for deep scleral invasion have been unpredictable or unacceptable compared with surgery.

Keratins in health and cancer: more than mere epithelial cell markers

Keratins are the intermediate filament (IF)-forming proteins of epithelial cells. Since their initial characterization almost 30 years ago, the total number of mammalian keratins has increased to 54, including 28 type I and 26 type II keratins. Keratins are obligate heteropolymers and, similarly to other IFs, they contain a dimeric central α-helical rod domain that is flanked by non-helical head and tail domains. The 10-nm keratin filaments participate in the formation of a proteinaceous structural framework within the cellular cytoplasm and, as such, serve an important role in epithelial cell protection from mechanical and non-mechanical stressors, a property extensively substantiated by the discovery of human keratin mutations predisposing to tissue-specific injury and by studies in keratin knockout and transgenic mice. More recently, keratins have also been recognized as regulators of other cellular properties and functions, including apico-basal polarization, motility, cell size, protein synthesis and membrane traffic and signaling. In cancer, keratins are extensively used as diagnostic tumor markers, as epithelial malignancies largely maintain the specific keratin patterns associated with their respective cells of origin, and, in many occasions, full-length or cleaved keratin expression (or lack there of) in tumors and/or peripheral blood carries prognostic significance for cancer patients. Quite intriguingly, several studies have provided evidence for active keratin involvement in cancer cell invasion and metastasis, as well as in treatment responsiveness, and have set the foundation for further exploration of the role of keratins as multifunctional regulators of epithelial tumorigenesis.

Acantholytic squamous cell carcinoma of the gingiva: report of a case and review of the literature

Adenoid squamous cell carcinoma differs from common squamous cell carcinoma in histologic features and its aggressive nature. Microscopically, the tumor shows cystic degeneration of the neoplastic epithelium, producing a prominent alveolar pattern and pseudoglandular structures with acantholytic cells. It occurs most commonly on the lips, rarely intraorally, and it is associated with a poor prognosis. This case concerns a 72-year-old woman who presented with the chief complaint of burning tongue and soreness of the lips. Clinical examination revealed an ulcerated and elevated mass on the edentulous left maxillary ridge, beneath the base of a partial denture. An incisional biopsy rendered the diagnosis of adenoid squamous cell carcinoma. The patient was referred to a specialized maxillofacial surgery center for diagnostic work-up and treatment. She underwent partial maxillectomy and radiotherapy, and 17 months after treatment, she died of uncontrollable recurrence.

Cytology of head and neck squamous cell carcinoma variants

The most common diagnosis rendered with head and neck fine needle aspiration (FNA) biopsy is metastatic squamous cell carcinoma (SCC). While most cases of metastatic SCC pose little diagnostic difficulty, the diagnosis of metastatic histologic variants of SCC, often coupled with less common etiologies, can be more problematic. This manuscript reviews the clinicopathologic features of the histologic variants of upper aerodigestive tract SCC (verrucous, papillary, spindle cell, undifferentiated, acantholytic, and basaloid) and uncommon etiologies of head and neck SCC (human papillomavirus, Epstein-Barr Virus, and NUT midline carcinomas). Particular attention is paid to the cytologic features of these lesions. Differential diagnoses and the use of ancillary testing are discussed.

Obligate basal cell component in salivary oncocytoma facilitates distinction from acinic cell carcinoma

The differential diagnosis between benign salivary oncocytoma (ONC) and low-grade malignant acinic cell carcinoma (ACC) can be difficult due to a significant histomorphological overlap of the structural and cytological presentation of both tumor types. To the best of our knowledge a comprehensive study comparing (immuno-)histological markers in cases of difficult differential diagnosis between ONC and ACC has not yet been performed. We investigated a panel of different immunohistochemical (CK5/6, CK14, CK7, CK18, p63 and Ki67) and histochemical (PAS, alpha-amylase) markers in 12 cases of ONC and 19 cases of ACC. The statistically significant stronger expression of CK7 in ONC and stronger expression of PAS and alpha-amylase in ACC in routine practice each is hampered by a pronounced overlap between both tumor groups. The obligate presence of an additional small basal cell component in all cases of ONC, demonstrable with p63 and CK5/6, enables a straightforward distinction from ACC, being constantly devoid of a basal cell component. Unexpectedly, CK14 is not a suitable marker for a reliable proof of these basal cells. The detection of this basal cell component in ONC in routine Hematoxylin-eosin stain is difficult and in some cases not possible; therefore, immunohistochemistry with p63 or CK5/6 is recommended for selected cases.

CK7+/CK20- immunoexpression profile is typical of salivary gland neoplasia

AIMS

To evaluate cytokeratin (CK) 7/20 expression patterns in salivary gland neoplasia.

METHODS AND RESULTS

Formalin-fixed paraffin embedded tissue from 153 salivary gland tumours were evaluated for CK7/20 immunoreactivity. The tumours included pleomorphic adenoma (n = 24), myoepithelioma (n = 9), papillary cystadenoma (n = 3), oncocytoma (n = 2), adenoid cystic carcinoma (n = 22), mucoepidermoid carcinoma (n = 21), polymorphous low-grade adenocarcinoma (n = 21), carcinoma ex-pleomorphic adenoma (n = 11), acinic cell carcinoma (n = 17), epimyoepithelial carcinoma (n = 7), oncocytic carcinoma (n = 3), hyalinizing clear cell carcinoma (n = 1), papillary cystadenocarcinoma (n = 1), salivary duct carcinoma (n = 3), adenocarcinoma (not otherwise specified) (n = 4) and squamous carcinoma (n = 4). Immunohistochemical procedures were performed using monoclonal antibodies CK7 (OV-TL 12/30), CK20 (Ks 20.8) and M3515 cytokeratin (AE1/AE3) in the presence of appropriate controls. The results were expressed semiquantitatively, according to the estimated percentage of positive tumour cells: 1+, 5-25%; 2+, 26-75%; and 3+, 76-100%. All salivary gland neoplasms showed a CK7+/CK20- immunoprofile ranging from 5 to 100%. Squamous carcinoma showed negative CK7/20 immunoexpression.

CONCLUSIONS

Although the CK7/20 immunoprofile is not useful in distinguishing the various types of salivary gland neoplasms or between benign and malignant salivary gland tumours, it may facilitate differentiation of primary salivary gland neoplasia from metastatic tumours and squamous carcinoma, and the diagnosis of metastatic salivary gland tumours.

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

AIMS

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

METHODS AND RESULTS

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

CONCLUSION

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

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

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

Conjunctival Mucoepidermoid Carcinoma in a Patient with Ocular Cicatricial Pemphigoid and a Review of the Literature

Invasive mucoepidermoid carcinoma of the conjunctiva of the left lower eyelid was diagnosed in an orbital exenteration specimen of a 57-year-old woman, after a biopsy of the same lesion was originally diagnosed as invasive squamous cell carcinoma. The woman was undergoing mitomycin C injections for ocular cicatricial pemphigoid, diagnosed in the same eye 2 years prior to identification of the neoplasm. The tumor invaded the cornea, sclera, lacrimal gland, regional small nerves, and lymphatics, but did not show intraocular involvement. The original biopsy specimen was reassessed with stains for mucin and found to be mucoepidermoid carcinoma of the conjunctiva. We reviewed 21 cases of mucoepidermoid carcinoma of the conjunctiva described to date in the English literature. We believe this number underestimates the true incidence of this condition, as it is frequently misdiagnosed both clinically and histopathologically. Evaluating suspected aggressive squamous cell carcinoma with special stains for mucin generally helps to identify mucoepidermoid carcinoma of the conjunctiva. More extensive surgical excision than that used for squamous cell carcinoma should be implemented in the management of mucoepidermoid carcinoma of the conjunctiva to prevent recurrence.

Mapping of candidate tumor suppressor genes on chromosome 12 in adenoid cystic carcinoma

Adenoid cystic carcinoma (ACC) is a common malignancy of salivary glands, for which the underlying genetic mechanisms of tumorigenesis are poorly understood. Prior studies in ACC have identified deletions in chromosome 12. To further characterize these changes, we performed an extensive LOH analysis in 58 ACC using a panel of 28 microsatellite markers. Results show 66% overall genetic loss. Three markers (D12S1713, D12S2196, D12S398) are contiguous and define a 6.84 Mb region of deletion at 12q13.11-q13.13. Two other markers (D12S2078, D12S1628) are also contiguous and define a 4.5 Mb region of deletion at 12q24.32-q24.33. The three remaining markers, D12S1056 at 12q14.1, D12S1051 at 12q23.1 and D12S1636 at 12q23.3 define smaller regions of deletion. An analysis of microarray gene expression profiling data available for ACC shows several genes with significant transcriptional downregulation that map to these areas of genetic deletion. This combined genetic and genomic analysis provides several candidate genes to test for functional tumor suppressor activity in ACC.

Unique expression of MUC3, MUC5AC and cytokeratins in salivary gland carcinomas

The differential diagnosis of salivary gland carcinoma is often difficult because of the confusing histopathological features of the different types of salivary gland carcinomas. The expression of MUC3, MUC5AC, MUC6, cytokeratin (CK)7 and CK20 was studied in 20 mucoepidermoid carcinomas (MEC), 20 adenoid cystic carcinomas (AdCC), and 11 acinic cell carcinomas (ACC). All the cases (51/51, 100%) were positive for CK7, but they were not positive for CK20. All the cases (100%) of the MEC were positive for MUC5AC, while all MEC (100%) were negative for MUC3. Only two cases (10%) were positive for MUC6. All cases (100%) of AdCC were negative for MUC3, MUC5AC and MUC6. Eight cases (73%) of ACC were positive for MUC3, but all the cases (100%) were negative for MUC5AC and MUC6. It is concluded that the positive expression of MUC5AC is very unique to MEC, and that the positive expression of MUC3 is very unique to ACC. These findings will be very useful for the differential diagnosis of the salivary gland carcinomas.

MUC1, MUC2, MUC4, and MUC5AC expression in salivary gland mucoepidermoid carcinoma: diagnostic and prognostic implications

We determined whether immunostaining for mucins could provide a better characterization of salivary gland mucoepidermoid carcinoma (MEC). We investigated 63 MECs by immunohistochemistry for MUC1, MUC2, MUC4, and MUC5AC. Mucin expressing cell types and labeling patterns were recorded. The results were compared with microscopic grade, tumor-associated lymphoid infiltrate, mucin expression in surrounding salivary glands, clinical features, and outcome. MUC1 and MUC4 labeled the apical membrane of glandular tumor cells and the entire membrane of intermediate, clear, and epidermoid tumor cells. MUC2 and MUC5AC were expressed in the cytoplasm of glandular, mucous, and intermediate tumor cells. In contrast to MUC1, MUC4 expression decreased with tumor grade (P < 0.01). Unlike MUC2, MUC5AC was expressed in more than 50% of high-grade tumors, including 2 cases that were not stained with Alcian blue. MUC1 and MUC5AC were associated with tumor-associated lymphoid infiltrates (P < 0.05), but not with tumor-associated lymphoid follicles. The proportions of tumors expressing mucins were 71% for MUC1, 21% for MUC2, 79% for MUC4, and 68% for MUC5AC. MUC1 and MUC5AC were more frequently expressed in tumors than in surrounding glands (P < 0.0001). MUC1 expression correlated with shorter progression-free survival (P < 0.05). In conclusion, mucin expression in MEC differs from that in salivary glands. Intermediate cells express MUC1 and MUC4 all along their cell surface and MUC2 and MUC5AC in their cytoplasm. Staining for MUC5AC in high-grade tumors can be helpful for distinguishing high-grade MEC from squamous cell carcinoma. While MUC4 is related to tumor differentiation, MUC1 expression indicates a worse prognosis.