Pleomorphic adenoma with extensive squamous metaplasia and keratin cyst formations in minor salivary gland: a case report

Pleomorphic adenoma (PA), the most common salivary gland tumor, accounts for 54 to 65 percent of all salivary gland neoplasias and 80 percent of the benign salivary gland tumors. It most frequently affects the parotid gland, followed by the submandibular and the minor salivary glands. Microscopically, mucous, sebaceous, oncocytic and squamous metaplasia, sometimes with the formation of keratin pearls, may be present, but the latter rarely results in the formation of extensive keratin-flled cysts lined by squamous epithelium. Extensive squamous metaplasia can be mistaken for malignancy, including mucoepidermoid carcinoma and squamous cell carcinoma. Here, we present an unusual case of PA with extensive squamous metaplasia and keratin cyst formations in a minor salivary gland, and discuss its microscopic features, including the immunohistochemical characteristics, and differential diagnosis of this uncommon presentation.

Expression of CD99 in Pleomorphic Carcinomas of the Lung

Pleomorphic carcinoma of the lung (PCL) is characterized by a mixture of sarcomatoid and carcinoma components, and a poor prognosis. However, no immunophenotype of tumor markers has been characterized in PCL. To charaterize the immunophenotype for CD99 in PCL, we performed an immunohistochemical evaluation of PCLs for thyroid transcription factor-1 (TTF-1), cytokeratin (CK) 7 and 20, and for CD99. CD99 was found to be expressed in both carcinomatous (47%) and sarcomatous components such as spindle cells (92%) and giant cells (57%). In the case of spindle cells, CK7 was expressed in 6 cases (46%) and TTF-1 in 2 cases (15%), whereas for giant cells CK7 was expressed in 8 cases (57%) and TTF-1 in one case (7%). However, CK20 was not expressed in either the carcinomatous or sarcomatous components in any case. Thus, CD99 was found to be widely expressed in both sarcomatous and carcinoma component in PCL. A clinicopathological analysis showed no direct correlation between the expression of CD99 and the clinical indices (stage, survival rate, invasion) of PCL.

RET/PTC and CK19 Expression in Papillary Thyroid Carcinoma and Its Clinicopathologic Correlation

Recently, the rearrangement of RET proto-oncogene has been reported to be the most common genetic change in papillary thyroid carcinoma (PTC). However, its prevalence has been reported variably and its relation to clinical outcome has been controversial. The characteristic nuclear features of PTC usually render the diagnosis, but problem arises with equivocal cytologic features that are present focally. Although there remains some controversy, CK19 has been reported to be a useful ancillary tool for diagnosis of PTC. To evaluate the expression rate of RET/PTC rearrangement and CK19 in PTCs in a Korean population, we studied 115 papillary thyroid carcinomas in 3 mm-core tissue microarray based immunohistochemical analysis. The prevalence of Ret protein expression was 62.6% and the CK19 immunoreactivity was 80.9%. There was no statistically significant asso-ciation between the Ret positivity and CK19 immunoreactivity, although the percent agreement of the two was relatively high. The clinicopathological variables did not correlate with the expression of Ret. In conclusion, the prevalence of Ret protein expression and its clinicopathological implications in a Korean population are not much different from those reported in previous studies. However, its detection via immunohistochemistry can be a useful diagnostic tool for diagnosing papillary thyroid carcinoma in conjunction with CK19.

Expression Patterns of Cytokeratins in Cholesteatomas: Evidence of Increased Migration and Proliferation

Aural cholesteatoma is characterized by invading squamous epithelia with altered growth properties. Cytokeratin (CK) expression is affected in epidermal proliferative diseases and represents the alterations of keratinocyte proliferation, differentiation, and migration. In the present study, the intensity of CK immuno-expression was determined, using densitometry at various sites in experimental cholesteatoma in order to characterize changes of keratinocytes. With cholesteatoma formation, CK4, a marker for non-keratinizing epithelia, increased in the suprabasal layers of the annular external auditory canal (EAC) and at the pars tensa indicating an altered differentiation and migration of keratinocytes. CK5/6, a marker of keratinizing squamous epithelium, increased only at the pars tensa of the tympanic membrane, indicating basal keratinocyte hyperplasia. CK1/10 increased in the suprabasal layer at the annular EAC, and at the peripheral pars tensa, indicating increased terminal differentiation of keratinocytes. CK13/16, markers of differentiation and hyperproliferation, increased in suprabasal layer of the EAC, and at the peripheral pars tensa. However, it decreased in the basal layer of the EAC, indicating hyperproliferation and migration of keratinocytes. The findings of this study support the basal cell hyperplasia hypotheses for the pathogenesis of aural cholesteatoma, with regard to hyperproliferation, migration, and an altered differentiation of keratinocytes.

Mixed Tumor of the Vagina: A Case Report

We report a case of mixed tumor arising in the lower vaginal wall. The patient was a 20-yr-old nullipararous woman. The tumor was relatively well-defined with expansile margin, and showed solid sheets or fascicles of stromal-type spindle cells and ovoid epithelial cells with sparsely scattered nests of mature squamous epithelium and glands lined by mucinous epithelium. Cellular atypia was not conspicuous, however, mitosis was counted upto 6 per 10 high power fields. We examined this tumor immunohistochemically and ultrastructurally and reviewed the articles to identify the histogenesis. Positive reaction for vimenin and cytokeratin of stromaltype spindle cells and presence of desmosome-like structures and tonofilaments on electron microscopic examination suggested the epithelial origin of the stromaltype spindle cells.

Detection of K19 mRNA compared with tumour markers in peripheral blood from breast cancer patients

A rise in peripheral blood of the glycoproteins carcino-embryonic antigen [CEA] and CA15.3 may be indicative of a subsequent clinical relapse and provides a useful adjunct in the management of metastatic breast cancer. We wished to study the relationship of these tumour markers with the expression of keratin 19 [K19] mRNA as a marker of epithelial cancer cells in periodic blood samples taken from patients undergoing postoperative therapy. CEA and CA15.3 were measured by radio-immunoassay while K19 mRNA was assessed by gel electrophoretic separation after a 40-cycle polymerase chain reaction amplification. Analysis of 395 samples [regardless of patient] showed concurrence in the detection of K19 and CEA and CA15.3 [using positivity cut-offs of 3.2 ng/ml and 32 U/l, respectively] in <20% of cases that were K19+ and in >80% for samples that were K19-. The frequency of CEA and CA15.3 positivity was related to the amount of K19 product. For 65 patients with 2-3 samples collected at 6 monthly intervals, we observed complete agreement for detection of these markers [at each occasion] in about 30% of cases only. Conclusions: These discrepancies may be due partly to the currently qualitative nature of the K19 assessment and emphasize the need for quantification of this but may also reflect a difference in the source of the signals, i.e. K19 originating from circulating cells and CEA/CA15.3 shed from solid tumour deposits. It is likely that K19 detection is more sensitive, but it is less certain which of these markers reflects a significant systemic tumour load and hence is of greater value in predicting relapse

Cytokeratin expression in human fetal tongue and buccal mucosa.

Expression of cytokeratins (CK), a subset of intermediate filament (IF) proteins in epithelia, is developmentally regulated. CK expression may also change after malignant transformation. Our earlier studies on CK expression in human oral tumours and pre-cancerous lesions have shown specific changes in CK expression. We analysed CK expression in human tongue and buccal mucosa (BM) in fetuses in the embryonic age group of 16 to 27 weeks using biochemical and immunohistochemical techniques to find out whether there is any similarity in CK expression in human oral squamous cell carcinomas (SCC) and fetal oral tissues. CK 1, 8 and 18 were detected in a majority of samples using both techniques. Our earlier studies had shown aberrant expression of CK 1 and 18 in many of the oral SCC and leukoplakias. Studies by immunohistochemistry showed that these different CK antigens were expressed in different cell layers. CK 1(2) were present in the stratified epithelial layers whereas CK 8 and 18 were restricted to glandular epithelium. Till 27 weeks of gestation, both tongue and BM expressed CK 1, 8 and 18 along with CK 6 and 16. Thus, fetal tissues showed some similarities in CK pattern with their respective SCC.

Replanteo de las funciones de los queratinocitos / Restate of the keratinocytes functions

Los queratinocitos intervienen activamente en la formación de una barrera mecánica, fisicoquímica e inmunológica. En su evolución centrífuga elaboran queratinas y otras proteínas no estructuradas, las que intervienen en el proceso de queratinización de los epitelios, con y sin estrato córneo. Durante la citodiferenciación adicionan nuevas queratinas, cuyo peso molecular aumenta a medida que las células migran hacia la superficie. La composición química de las queratinas sintetizadas y retenidas por ellos, guarda relación con las variantes histológicas del epitelio bucal. El modelo específico de sus componentes polipeptídicos permite caracterizar cada epitelio. Los queratinocitos también participan en el proceso inmunológico local. Intervienen en la maduración post-tímica e instrucción de algunos linfocitos. Inducen a las células T inmaduras a sintetizar la enzima TdT. Producen sustancias parecidas a las hormonas y excretan interleuquina-1. En gingivitis crónicas, liquen plano y algunas enfermedades cutáneas, expresan antígeno de histocompatibilidad HLA-DR involucrándose, en los procesos inflamatorios, en el reconocimiento y presentación de antígenos a los linfocitos T