Expression of cytokeratins in Warthin's tumour (adenolymphoma) of parotid glands: specific detection of individual cytokeratin types by monoclonal antibodies

Microcystic adnexal carcinoma: an immunohistochemical reappraisal

Even though immunohistochemical comparisons of microcystic adnexal carcinoma vs infiltrative basal cell carcinoma and desmoplastic trichoepithelioma exist, they are mostly restricted to the use of a single stain. In addition, a comparison with squamous cell carcinoma has not been reported previously. In this study, we compare the expression of cytokeratin (CK) 15, CK7, CK20, CK903, carcinoembryonic antigen (CEA), CD10, CD15 and BerEP4 in 13 microcystic adnexal carcinoma, eight desmoplastic trichoepithelioma, 10 infiltrative basal cell carcinoma, and eight squamous cell carcinoma of which five exhibited ductal differentiation. We found that the majority of microcystic adnexal carcinoma (92%) and desmoplastic trichoepithelioma (100%) cases expressed CK15 while the infiltrative basal cell carcinoma and squamous cell carcinoma cases were all negative. Forty percent of infiltrative basal cell carcinoma expressed CK7; while only two microcystic adnexal carcinoma cases (15%) and one squamous cell carcinoma with ductal differentiation (12%) expressed CK7 in the remaining three tumor categories. None of the desmoplastic trichoepithelioma expressed CK7. All tumors were strongly positive for CK903. While the neoplastic cells were negative, luminal staining of ductal structures was noted for CK7, CD15 and CEA in some of the microcystic adnexal carcinoma, desmoplastic trichoepithelioma and squamous cell carcinoma with ductal differentiation cases. Sixty percent of infiltrative basal cell carcinoma, 31% of microcystic adnexal carcinoma, and 25% of squamous cell carcinoma express CD10. BerEP4 expression was noted in 38% of microcystic adnexal carcinoma, 57% of desmoplastic trichoepithelioma, 100% of infiltrative basal cell carcinoma, and 38% of squamous cell carcinoma. In conclusion, we found CK15 to be a useful marker in distinguishing microcystic adnexal carcinoma from infiltrative basal cell carcinoma and squamous cell carcinoma with ductal differentiation. Our experience indicates that microcystic adnexal carcinoma and desmoplastic trichoepithelioma have a similar immunohistochemical profile that is, CK15+ and BerEP4+/-; thus, additional studies are needed to separate these two entities.

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.

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.

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

On the basis of the heterogeneity of cytokeratins 7 and 20 expression in malignant epithelial tumors, the cytokeratin 7/20 immunophenotype has served as a useful diagnostic tool for discrimination of primary and/or metastatic carcinomas of unknown origin. However, the expression pattern of these cytokeratins in malignant salivary gland tumors has not been thoroughly studied. Our study material was composed of 84 malignant tumors of primary major or minor salivary gland origin. Nine histologic types of carcinoma were represented, including mucoepidermoid (26 cases), adenoid cystic (25), polymorphous low grade (11), salivary duct (8), acinic cell (4), ex mixed tumor (3), not otherwise specified (3), clear cell (2), and basal cell (2). In all, 13 cases of primary skin or mucosal squamous cell carcinoma with secondary salivary gland involvement were also examined. Immunoreactivity for cytokeratin 7 was evident in all malignant salivary gland tumors; the staining pattern was diffuse and strong in 62 cases, and focal and strong in 22 cases. In contrast, 78 cases were negative for cytokeratin 20, whereas only six cases (two mucoepidermoid, one adenoid cystic, and three salivary duct) displayed focal weak positivity. Overall, 92.9% of malignant salivary gland tumors were characterized by a cytokeratin 7 positive/20 negative immunoprofile, the remaining 7.1% of cases being positive for both cytokeratins. The latter phenotype was more common in salivary duct carcinomas (P< or =0.05). On the other hand, most squamous cell carcinomas (69%) were negative for both cytokeratins, while the remaining cases (31%) were negative for cytokeratin 20 and focally weakly positive for cytokeratin 7. We suggest that assessment of cytokeratin 7/20 immunoprofile may facilitate the differential diagnosis of (a) primary malignant salivary gland tumors from metastatic tumors, (b) metastatic salivary gland tumors, (c) primary salivary gland tumors, especially mucoepidermoid carcinomas, from squamous cell carcinomas, and (d) salivary duct carcinomas from other malignant salivary gland tumors.

Warthin's tumour: a study of 78 cases with emphasis on bilaterality, multifocality and association with other malignancies

The authors reviewed the clinical records and the histopathological preparations of 78 cases of Warthin's tumours (WTs), treated at the Department of Dental Sciences, Centre for the Study of Oral Tumours, of the University of Bari. All the surgical specimens had been fixed in neutral buffered formalin, sampled according to the step-serial, whole-specimen sectioning technique, embedded in paraffin and stained with haematoxylin-eosin, periodic acid Schiff and Gomori's reticulin. The results showed that Warthin's tumours characteristically affect the parotid gland, and most frequently arise in adults (mean age=57 years) and in males (95%). Multiple tumours were detected in 16 cases (20.5%), and five of these were bilateral (6.5%). One of the multifocal tumours involved an intra-parotideal lymph node and the laryngeal piriform sinus. In addition, 13 cases (16.6%) were associated with other malignancies. These data indicate that multiple (synchronous or metachronous) WTs may occur more frequently than previously reported. The high rate of multiple WTs detected in the current study may result from extensive and accurate sampling of these neoplasms for histopathological evaluation. Consequently, complete preoperative work-up of patients harbouring parotideal tumours consistent with or suspicious for WT is necessary. The work-up should include CT scans and/or magnetic resonance imaging of both parotid glands, to exclude the occurrence of multiple tumours, which may be clinically undetectable. Also, fine needle aspiration biopsy may be an accurate tool for excluding malignant neoplasms and for better planning subsequent surgical procedures. These usually consist in (bilateral) superficial parotidectomy and should be followed by long term follow up of the patients, in view of possible metachronous WTs, even after prolonged time intervals.

Cytokeratin expression and epithelial differentiation in Warthin's tumour and its metaplastic (infarcted) variant

AIMS

Warthin's tumour is characterized by a bilayered columnar epithelium. Transformation into metaplastic (infarcted) Warthin's tumour includes squamous metaplasia of the epithelium along with regressive changes in the stroma. Misinterpretation of metaplastic Warthin's tumour for malignancy is a serious diagnostic pitfall. This study assesses the utility of cytokeratin expression in Warthin's tumour and its metaplastic variant.

METHODS AND RESULTS

Twenty-six cases of Warthin's tumour, among them eight metaplastic Warthin's tumours, were investigated employing immunohistochemistry. Both Warthin's tumour and its metaplastic variant regularly expressed cytokeratins (CK) 7, 8, 18, and 19. Staining results with antibodies to CK10, 10/13, 1/2/10/11, and 20 were negative in all specimens. Immunoreactivity for CK 5/14 and 17 was restricted to basal cells in Warthin's tumour, but involved basal as well as surface cells in metaplastic Warthin's tumour.

CONCLUSIONS

Warthin's tumour and its metaplastic (infarcted) variant both express CK 7, 8, 18, and 19, which are typical for columnar differentiation. Cytokeratins typical of squamous differentiation are absent from Warthin's tumour and its metaplastic variant, irrespective of the squamous morphology of the epithelium in metaplastic Warthin's tumour. The expression of CK 5/14 and 17, which are typical of regenerative cells, is restricted to basal cells in Warthin's tumour, but is expressed also in surface cells in metaplastic Warthin's tumour.

Microcystic adnexal carcinoma: an immunohistochemical study including markers of proliferation and apoptosis

Microcystic adnexal carcinoma (MAC) is the prototype for a subset of locally aggressive adnexal carcinomas (LAACs). Ultraviolet radiation (UVR) and UVB signature p53 mutations are implicated in the etiology of the most common cutaneous carcinomas. However in MACs, the role of UVR and p53 mutations is unknown. In addition, controversy still exists regarding the patterns of differentiation within these tumors. The objective of this study was to determine the expression patterns of immunohistochemical markers for p53, Ki-67, c-erbB-2, and Bcl-2 in MACs, and to compare these patterns with two MAC histologic stimulants: sclerosing type basal cell carcinomas (sBCCs) and desmoplastic trichoepitheliomas (dTEs). Other objectives were to compare expression patterns of cytokeratin (CK) AE1/AE3, CK7, CD20, endothelial membrane antigen (EMA), Ber-EP4, CD34, alpha-smooth muscle actin (SMA), and S-100 protein in MACs with its histologic simulators, and to determine the usefulness of all the immunohistochemical studies in diagnosis. Immunohistochemical markers were performed on 10 MACs, 10 sBCCs, and four dTEs. They included p53, Ki-67, c-erbB-2, Bcl-2, CK AE1/AE3, CK7, CD20, EMA, Ber-EP4, CD34, S-100 protein, and alpha-SMA. MACs expressed p53 in less than 25% of the tumor cells in only two cases (20%), and both cases showed only moderately intense staining, whereas 80% of the sBCCs were positive and showed intense staining, and all dTEs were negative. In MACs, less than 5% of the tumor cells were Ki-67 positive, whereas the sBCCs showed 20% to 40% Ki-67-positive tumor cells and dTEs showed rare Ki-67-positive cells. Bcl-2 was expressed focally in MACs, diffusely in sBCCs, and in scattered cells in dTEs. All tumors were negative for c-erbB-2. CD34, CK7, EMA, Ber-EP4, S-100 protein, and alpha-SMA all showed a distinctive pattern of staining in MACs. Although MACs arise commonly in chronically sun-exposed skin, increased expression of p53 is not found frequently. Overexpression of c-erbB-2 does not appear to be a factor in the development and progression of these adnexal tumors. Bcl-2 is expressed in MACs, but not diffusely as in sBCCs. The low level of Ki-67 supports a low proliferative rate, and other immunohistochemical markers support divergent patterns of adnexal differentiation in MACs. Immunohistochemical studies may help to differentiate MAC from sBCCs and dTEs.