Cytokeratin 14 expression in epithelial neoplasms: a survey of 435 cases with emphasis on its value in differentiating squamous cell carcinomas from other epithelial tumours

AIMS: The tissue distribution of cytokeratin 14 (CK14) in epithelial neoplasms is not well defined. We have evaluated 435 cases of epithelial neoplasm of various origins with cytokeratin 14 monoclonal antibody with special attention to possible use in differential diagnosis. METHODS AND RESULTS: Immunohistochemistry (ABC-HRP method) was performed for detection of CK14. We found that the expression of cytokeratin 14 was generally restricted to: (i) the majority of cases of squamous cell carcinoma regardless of origin (67/74) and degree of differentiation; (ii) neoplasms with focal squamous differentiation, including endometrial, and ovarian adenocarcinoma, malignant mesothelioma and transitional cell carcinoma; (iii) thymoma (8/8); (iv) myoepithelial components of salivary gland pleomorphic adenoma (3/4); and (v) oncocytic neoplasms, including thyroid Hurthle cell adenoma (1/1) and salivary gland Warthin's tumour (2/2). CONCLUSION: CK14 protein is a useful marker in differential diagnosis of squamous cell carcinomas.     

Malignant mixed tumour

Summary Two malignant mixed tumours, in which both carcinomatous and sarcomatous features were present, are described. They arose in the palate in patients who had undergone surgery and irradiation for a pleomorphic adenoma at the same site 30 and 36 years previously.The histological differential diagnoses of recurrent benign pleomorphic adenoma, pleomorphic adenoma resembling mesenchymal tumour, and carcinoma in (ex) pleomorphic adenoma are discussed. On the basis of their positive reaction for keratin with specific monoclonal antibodies it is suggested that the myoepithelial cells are of epithelial origin. Immunohistochemical studies together with the histological appearance of the neoplasms indicate that the carcinomatous as well as the sarcomatous elements were derived from modified myoepithelial tumour cells.Irradiation may have been responsible for inducing a true malignant mixed tumour as distinct from the more common malignancy which may arise in pleomorphic adenoma, this being a simple carcinoma.This work was partly presented at the 151th Meeting of the Pathological Society of GreatThis work was partly presented at the 151th Meeting of the Pathological Society of Great     

Carcinosarcoma of the parotid gland: cytological, clinicopathological and immunohistochemical study of a case

Manifesting a putative origin from a pleomorphic adenoma, carcinosarcoma of the salivary gland is a heterologous neoplasm in which a sarcomatous and a carcinomatous component coexist. We present a parotid gland carcinosarcoma in a 77-year-old man with peculiar morphological findings. Fine-needle aspiration cytology allowed a preoperative diagnosis of poorly differentiated carcinoma. At histologic examination, the tumor showed biphasic differentiation with an epithelial component made up of well-differentiated keratinizing squamous carcinoma and ductal-type adenocarcinoma, and a mesenchymal component, revealing focal areas of osteosarcoma and myoepithelial malignant proliferation. Carcinosarcoma is a very rare malignant neoplasm, accounting for 0.16% of malignant salivary gland tumors: only 60 cases have been reported, some of which arose "de novo", i.e., without clinico-pathologic evidence of a pre- or co-existing pleomorphic adenoma.     

Lymphatic vascular density and lymphangiogenesis during tumour progression of carcinoma ex pleomorphic adenoma

AIMS: To assess lymphatic vascular density (LVD) and lymph vessel endothelial proliferation in a series of carcinoma ex pleomorphic adenoma (CXPA) that represents the tumour in the different carcinogenesis phases and tumour progression. METHODS: In 8 cases of early CXPA (intracapsular and minimally invasive tumours), 8 of advanced CXPA (widely invasive tumours) and 10 of pleomorphic adenoma (PA) without malignant transformation, lymphatic vessels and proliferating cells were detected using the antibodies D2-40 and Ki-67 respectively. RESULTS: Comparing early tumours with advanced ones, LVD was not significantly different at the tumour margin. In contrast, regarding intratumoural lymphatics, PA without malignant transformation and early CXPA contained rare, if any, lymph vessels, whereas in widely invasive carcinomas they were more numerous. However, neither intratumoural nor peritumoural LVD were increased in comparison to adjacent normal salivary gland tissue. In no case did dual immunohistochemistry using D2-40 and the cell proliferation marker Ki-67 reveal the existence of proliferating lymphatics. Carcinomatous emboli were found in peritumoural as well as in intratumoural lymphatics only in advanced CXPA without myoepithelial differentiation. CONCLUSION: In CXPA, the lymphatic network is mainly composed of pre-existing lymphatics which are rare in tumours that have not infiltrated outside the confines of the original PA. In the widely invasive CXPA, intratumoural as well as peritumoural lymphatics are a conduit for carcinoma cells, but in carcinomas with myoepithelial differentiation, the neoplastic cells seem to have a lower invasion capacity.     

Immunoexpression of c-erbB-2 and p53 in benign and malignant salivary neoplasms with myoepithelial differentiation.

AIM: To evaluate whether the immunoexpression of c-erbB-2 and p53 is involved in the pathogenesis and progression of salivary tumours with myoepithelial differentiation. METHODS: 233 tumours from 211 patients were studied. These included 76 primary and 24 recurrent adenocarcinomas (polymorphous low grade adenocarcinoma, 13; epithelial-myoepithelial carcinoma, 19; adenoid cystic carcinoma, 56; and basal cell adenocarcinoma, 12) and 133 pleomorphic adenomas and myoepitheliomas, 96 being primary and the remaining recurrent tumours. All cases were formalin fixed and paraffin wax embedded. A StrepABC peroxidase method and polyclonal c-erbB-2 and p53 specific antisera were used. RESULTS: Cell membrane staining of c-erbB-2 was not found in any benign or malignant tumour. There was p53 protein accumulation in one primary and one recurrent pleomorphic adenoma and in 10 adenocarcinomas (polymorphous low grade adenocarcinoma, one; epithelial-myoepithelial carcinoma, one; adenoid cystic carcinoma, five; and basal cell adenocarcinoma, three), three of them being recurrences. CONCLUSIONS: The c-erbB-2 and p53 proteins are not involved in the pathogenesis of pleomorphic adenoma and myoepithelioma and do not constitute biomarkers in assessing the risk of recurrence. c-erbB-2 is not involved in the genesis of low grade salivary neoplasia with myoepithelial differentiation. The percentage of this type of neoplasia with p53 accumulation is low (10%) and does not appear to be related to tumour recurrence.     

Pleomorphic adenoma (benign mixed tumor) of the breast. An immunohistochemical, flow cytometric, and ultrastructural study and review of the literature

Pleomorphic adenoma (or benign mixed tumor) of the breast is a rare benign neoplasm that might be misinterpreted both clinically and pathologically as a malignant tumor. The authors present an additional case of this unusual lesion studied by immunohistochemistry, electron microscopy, and flow cytometry. A 77-year-old white woman presented with a 2-cm, nontender, mobile, calcified, right subareolar mass suggestive of a fibroadenoma. Microscopically, the tumor resembled a pleomorphic adenoma occurring in salivary glands. Positive immunostaining for S-100 protein, cytokeratin, and muscle-specific actin, as well as the ultrastructural presence of intermediate filaments with dense bodies and intercellular junctions, supported the predominant myoepithelial cell differentiation within the tumor, whereas the epithelial cell component stained only with cytokeratin and contained formed lumina with surface microvilli. The DNA pattern was diploid. The patient is alive and well 14 months after surgery. The authors' findings confirm that pleomorphic adenoma of the breast is a benign neoplasm in which myoepithelial cell proliferation plays a major role in tumorigenesis.     

Ultrastructural analysis of salivary gland pleomorphic adenoma, with particular reference to myoepithelial cells

Previous ultrastructural studies of pleomorphic adenoma have presented conflicting results with regard to the role of myoepithelial cells in the histogenesis of this tumour. In the present study specimens of ten major salivary gland pleomorphic adenomas were examined ultrastructurally and a number of cell types identified. The material was subjected to quantification using the stereological method of point counting. The results showed a wide spectrum of differentiation within these tumours in which typical myoepithelial cells were rarely encountered even in situations where they are reported to occur in routine histological preparations. Cells with some myoepithelial features were more numerous but duct cells accounted for the majority of tumour cells. The ultrastructural findings correlated well with previously reported immunocytochemical data and further support certain ideas about salivary gland tumour histogenesis.     

Pleomorphic adenoma with bizarre myoepithelial cells: A diagnostic challenge on cytologic smear

The diagnosis on fine needle aspiration of salivary gland tumors with a myoepithelial component is challenging because myoepithelial cells can have a wide cytomorphologic spectrum. The authors report a case of a pleomorphic adenoma of the parotid gland that expands the spectrum of appearances that myoepithelial cells can show with this tumor. A 55‐year‐old female was found to have a right parotid gland mass. FNA showed hypercellularity, with loosely cohesive fragments of spindle‐shaped myoepithelial cells admixed with small nests of epithelial cells. Interspersed may occasional bizarre cells possessing severely pleomorphic nuclei with hyperchromasia. The cytologic diagnosis was “suspicious for carcinoma ex pleomorphic adenoma.” A total parotidectomy was performed with complete resection of the tumor that was confirmed to be a pleomorphic adenoma. The pleomorphic cells noted on FNA were scattered throughout the tumor, and were positive by immunostaining for keratin, S‐100 protein and p63, identifying them as myoepithelial cells. These cells did not show mitotic activity and were negative for Ki67. The pleomorphic adenoma showed extensive degenerative changes including central cyst formation, stromal hyalinization and hemosiderin deposition. On the basis of the combined light microscopic and immunohistochemical findings, there was no evidence to support a malignant change in the pleomorphic adenoma. It was concluded the pleomorphic myoepithelial cells were a degenerative change, reminiscent of what is seen in “ancient” schwannoma and some uterine leiomyomata. Our case expands the spectrum of appearances that can be seen in myoepithelial cells in the salivary gland.     

Carcinoma ex pleomorphic adenoma

Carcinoma ex pleomorphic adenoma is an epithelial malignant neoplasm arising from a primary or recurrent pleomorphic adenoma and is a diagnostic challenge for cytopathologists. Diagnosis requires that elements from the benign pleomorphic adenoma and the malignant component need to be seen. We report a case of carcinoma ex pleomorphic adenoma in a patient presenting with left facial nerve palsy and a painless left parotid lump. Ultrasound imaging revealed a suspicious parotid mass and FNA cytology showed background benign myoepithelial and ductal cells, chondro-myxoid stroma, and overtly malignant epithelial and myoepithelial cells; features consistent with carcinoma ex pleomorphic adenoma. A radical parotidectomy was performed and histology confirmed the diagnosis of invasive salivary duct carcinoma ex pleomorphic adenoma. Early diagnosis of carcinoma ex pleomorphic adenoma is important and cytology plays a key role; however, findings should be correlated with radiology and clinical history and the potential limitations of cytology should be appreciated.     

Ultrastructural similarities of adenoid cystic carcinoma and pleomorphic adenoma

Ultrastructural examination of five adenoid cystic carcinomas, three breast and two salivary gland, reveals identical patterns of tumour cell differentiation, organization and distribution of cellular products (Zaloudek, Oertel & Orenstein 1984). In both sites, there is proliferation of two populations of cells, one with characteristics and organization of duct-type luminal epithelial cells and a second that forms the principal proliferating component and has the overall organization and appearance that would suggest that they represent modified myoepithelial cells. Recent ultrastructural studies also indicate that tumour cell types and histological organization similar to those described for adenoid cystic carcinoma occur during histodifferentiation of salivary gland pleomorphic adenoma (Dardick et al. 1983a, b). The characteristic histological pattern of adenoid cystic carcinoma is dependent on the formation of pseudolumina containing proteoglycans and reduplicated basal lamina. Similar, but smaller, lumina of like organization and contents are evident in some cases of pleomorphic adenoma. Both the ultrastructural similarities of the tumour cell types and their organization, in adenoid cystic carcinoma and pleomorphic adenoma, suggest that these tumours have a similar histogenetic basis. The fact that one lesion is malignant and the other benign does not preclude common types of tumour cells and developmental processes.     

Fine‐needle aspiration (FNA) and pleural fluid cytology diagnosis of benign metastasizing pleomorphic adenoma of the parotid gland in the lung: A case report and review of literature

Lesions that contain abundant benign myoepithelial cells, including pleomorphic adenomas of salivary gland origin, may present a diagnostic challenge in fine‐needle aspiration (FNA) specimens. Benign metastasizing pleomorphic adenoma is a rare neoplasm, in which the benign appearing pleomorphic adenoma, without any histological evidence of malignancy, metastasizes to distant sites including lung. In the absence of clinical history of a pre‐existing myoepithelial neoplasm, the presence of myoepithelial cells in the lung or any other organs besides salivary glands may create diagnostic difficulty. Here we present the cytologic findings of such a metastatic tumor found in the lung FNA and pleural fluid specimens from a 64‐year‐old woman, with a history of local recurrent salivary gland pleomorphic adenomas, who presented with multiple bilateral pulmonary nodules and pleural effusion. The diagnosis of benign metastasizing pleomorphic adenoma was made based on clinical information and cytomorphology, and confirmed by immunocytochemistry. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.     

Pulmonary salivary gland-type tumors with features of malignant mixed tumor (carcinoma ex pleomorphic adenoma): a clinicopathologic study of five cases

We report 5 cases of pulmonary salivary gland-type tumors with features of carcinoma ex pleomorphic adenoma. Patient ages ranged from 44 to 71 years (mean, 53.8 years); 4 patients were men and 1 was a woman. In all 5 cases, the lesions were associated with the bronchial system. None of the patients had a history of a head and neck salivary gland neoplasm. Histologically, the lesions were invasive tumors containing malignant myoepithelial elements and duct-like structures embedded in a benign chondromyxoid stroma. Areas reminiscent of residual pleomorphic adenoma were noted in 2 cases. Follow-up for 3 patients revealed that 2 died 22 and 54 months after diagnosis and 1 was alive 20 months after diagnosis. The cases are characterized by unique morphologic features that, coupled with their immunoprofile, suggest the possibility that these tumors represent carcinoma ex pleomorphic adenoma, an entity that has not been well documented in the bronchopulmonary system.     

The effect of a reconstituted basement membrane (Matrigel) on a human salivary gland myoepithelioma cell line

We have already demonstrated that a reconstituted basement membrane (Matrigel) is a key modulator of morphogenetic changes and cytodifferentiation of pleomorphic adenoma cells in culture. Myoepithelioma is considered to be a neoplasm closely related to pleomorphic adenoma and should experience similar induction processes. Thus, the aim of this study was to investigate whether Matrigel would influence myoepithelioma cells. We used a cell line derived from a human salivary gland plasmacytoid myoepithelioma (M1 cells) grown in a three-dimensional preparation of Matrigel. Phenotype differences were assessed using conventional light microscopy technique (haematoxylin and eosin) and phase and differential interference contrast (Nomarski). Immunofluorescence was carried out to detect smooth-muscle actin, laminin and type-IV collagen. M1 cells exhibited all proteins studied, showing a myoepithelial differentiation. M1 cells grown inside Matrigel presented morphological changes and changes in smooth-muscle actin status. By growing M1 cells inside Matrigel, it was possible to reproduce the tumour architecture with no duct-like structures. Based on our findings, we suggest that myoepithelioma would be derived from a cell with a commitment to myoepithelial differentiation. We also suggest that the mechanical properties of the matrix environment will likely regulate smooth-muscle actin expression in myoepithelioma.     

Lipomatous pleomorphic adenoma of the parotid gland. Classification of lipomatous tissue in salivary glands.

Lipomatous pleomorphic adenoma is an unusual subtype with a lipomatous stromal component of more than 90% of the tumour tissue. This special type of pleomorphic adenoma must be distinguished from other types of lipomatous tumours or non-tumourous lipomatosis of the salivary glands. Until now only two cases of lipomatous pleomorphic adenoma have been reported in the literature. We report of a 36-year old woman who developed a well circumscribed nodule measuring 3.5 x 2.5 x 2 cm in the right parotid gland. The cut surface was grey-yellowish. Histologically, more than 90% of the tumour tissue was fatty tissue with univacuolar adipocytes. The pleomorphic epithelial elements were duct-like cells forming small lumina and spindle-shaped myoepithelial cell with surrounding mucoid stroma. Components of pleomorphic adenoma were intermingled with mature adipose tissue which was more concentrated in the central portion of the adenoma. Some compressed epithelial cords in the adipose tissue formed a septa-like pattern. The differential diagnosis to other lipomatous tumours (lipoadenoma, lipoma) and to non-tumourous interstitial lipomatosis as well as the possible pathogenesis as metaplastic change or epithelial-mesenchymal transdifferentiation are discussed.     

Myoepithelial carcinoma in pleomorphic adenoma of salivary gland type, occurring in the mandible of an infant

A rapidly growing mandibular tumor occurred in a 17 month old female infant. Tumor outgrowth showing a periosteal reaction was radiographically seen on the lower surface (base) of the mandible. Under the biopsy diagnosis of osteosarcoma, high-dose chemotherapy with methotrexate was performed, resulting in little effect. The right hemiman-dibulectomy specimen disclosed intraosseous infiltrative growth of pleomorphic adenoma of salivary gland type, associated with chondroid stroma and reactive bone formation. The highly proliferative small-sized cells retained immunohistochemical features of myoepithelial cells, with positive reactivity of cytokeratin, vimentin, S-100 protein, a-smooth muscle actin, epithelial membrane antigen, CA15–3, type IV collagen, laminin and p53 protein. No heterotopia of the salivary gland was identified within the bone tissue. The tumor recurred 2 months later. Due to uncontrollable local growth, the patient died 8 months after operation. At autopsy, reactive ossification was closely associated with malignant myoepithelial proliferation. No distant metastasis was noted. This osteosarcoma-like tumor can be regarded as myoepithelial carcinoma in pleomorphic adenoma, originating from intramandibular heterotopic salivary gland tissue.     

Myoepithelial differentiation markers in salivary gland neoplasia]

Salivary gland tumors frequently present myoepithelial cell differentiation that is not always easily identified on routinely stained sections. Recently novel markers of myoepithelium have been studied, such as calponin (CALP), caldesmon (CALD), and smooth muscle myosin heavy chain. These markers, together with smooth muscle actin may be useful tools for identifying myoepithelial cells. We immunohistochemically studied a series of 23 benign and malignant salivary gland tumors using antibodies to these four markers. The tumors were classified as follows: pleomorphic adenoma (n = 8), basal cell adenoma (n = 3), myoepithelioma with plasmacytoid cells (n = 2), epithelial-myoepithelial cell carcinoma (n = 6) and adenoid cystic carcinoma (n = 4). All tumors were positive for at least one of the four markers. CALP and smooth muscle actin were the markers more frequently expressed. Positivity was mostly located in the myoepithelial cells that constitute the external layer of the glandular or tubular neoplastic structures. In poorly differentiated epithelial myoepithelial carcinomas, composed of solid sheets of neoplastic cells and sometimes of clear cells, immunohistochemical staining for myoepithelial markers evidenced rudimentary glandular structures. CALP and smooth muscle actin were positive in the two cases of myoepithelioma with plasmacytoid cells. In conclusion, the combined staining with four markers helps to disclose myoepithelial cell differentiation and can be a useful tool for the correct histopathological diagnosis of salivary gland tumors. Among the four markers studied, CALP and smooth muscle actin were the most useful to identify myoepithelial cell differentiation.     

Maspin expression in carcinoma ex pleomorphic adenoma

AIMS: To investigate the presence and distribution of the protein maspin in carcinoma ex pleomorphic adenoma (CXPA).METHODS: Maspin expression was studied by means of immunohistochemistry in 16 cases of CXPA, using the labelled polymer method.RESULTS: According to the extent of invasion, the tumours were subdivided into: intracapsular (five cases), minimally invasive (four cases), and invasive (seven cases). Twelve patients had carcinoma with only epithelial differentiation, whereas four had a malignant myoepithelial component. Non-luminal cells in the duct-like structures of the remnant pleomorphic adenoma were strongly positive for maspin, whereas only a few luminal cells were immunopositive. A few positive cells were seen in the frequent hypocellular and hyalinised areas. Maspin was abundantly expressed, mainly in non-luminal cells, in transitional areas of CXPA with only epithelial differentiation. In frankly carcinomatous areas there was a gradual decrease in maspin expression. Almost all cells were maspin positive in CXPA with a myoepithelial component. When present, luminal cells were in general negative for maspin.CONCLUSIONS: When only epithelial cells undergo malignant transformation, maspin expression is gradually lost. In cases with a myoepithelial component, maspin expression is high, and this might be related to the tumour suppressor activity attributed to this cell.     

PLAG1 gene alterations in salivary gland pleomorphic adenoma and carcinoma ex-pleomorphic adenoma: a combined study using chromosome banding, in situ hybridization and immunocytochemistry.

Pleomorphic adenoma is the most common benign tumor of the salivary glands. It has marked histological diversity with epithelial, myoepithelial and mesenchymal-type cells arranged in a variety of architectural and differentiation patterns. Pleomorphic adenoma gene 1 (PLAG1), shown to be consistently rearranged in pleomorphic adenomas, is activated by chromosomal translocations involving 8q12, the chromosome region that is most frequently affected in these tumors. In this study, we evaluated PLAG1 involvement in salivary gland tumorigenesis by determining the frequency of its alterations in a selected group of 20 salivary gland tumors: 16 pleomorphic adenomas and four carcinomas ex-pleomorphic adenoma, having in common the presence of karyotypic chromosome 8 deviations, either structural, with 8q12 rearrangements, or numerical, with gain of chromosome 8. PLAG1 status was analyzed using in situ hybridization techniques, on metaphase cells, by fluorescence detection and/or interphase cells in paraffin sections, by chromogenic detection. Except for one pleomorphic adenoma case (5%) that lacked PLAG1 involvement, 17 tumors (85%), (14 pleomorphic adenomas and three carcinomas ex-pleomorphic adenoma) showed intragenic rearrangements of PLAG1 and the remaining two cases (10%), (one pleomorphic adenoma and one carcinoma ex-pleomorphic adenoma), had chromosome trisomy 8 only. To further investigate the role of PLAG1 on pleomorphic adenomas tumorigenesis, as well as the putative morphogenesis mechanism, we attempted to identify the cell types (epithelial vs myoepithelial) carrying 8q12/PLAG1 abnormalities by a combined phenotypic/genotypic analysis in four cases (three pleomorphic adenoma and one carcinoma ex-pleomorphic adenoma) characterized by 8q12 translocations and PLAG1 rearrangement. In these cases, both cells populations carried PLAG1 rearrangements. This finding further supports the pluripotent single-cell theory, which postulates that the tumor-initiated, modified myoepithelial cell, evolves into the varied somatic cell phenotypes present in pleomorphic adenoma, and reinforces the role of PLAG1 on the tumorigenesis of benign and malignant pleomorphic adenoma.     

Histogenetic and morphogenetic problems of pleomorphic adenoma of the salivary glands

Electron microscopic examinations of pleomorphic adenoma tissue showed epithelial and myoepithelial cell elements to take part in morphogenesis of both epithelial and "mesenchymal" zones. The epithelial component of pleomorphic adenoma is represented by cells showing signs of structural-functional differentiation of the squamous epithelium,, epithelium of terminal secretory parts of the salivary gland, and myoepithelial cells. The "mesenchymal" component is also represented by myoepithelial and epithelial cells. Differences in the structure of the epithelial and "mesenchymal" components are due to the pattern of arrangement and the functional status of the cells rather than to the set of the cell forms. A slow growth of the tumor and the marked functional activity of myoepithelial cells result in the accumulation of the substance of basal membranes released into the intercellular space, separation of the cells and degenerative changes in them. The results of ultrastructural examinations confirm the theory of the epithelial genesis of salivary gland pleomorphic adenoma. In this connection it sould be acknowledged that the term "mixed tumor" does not relate the essence of this neoplasia because the point at issue is a tumor of epithelial nature, whereas the term "pleomorphic adenoma" recommended by the WHO is more acceptable and emphasized the epithelial origin and heterogeneity of the cell composition and structures of the tumor.