舌下腺癌在多形性腺瘤中1例

发生于舌下腺的癌在多形性腺瘤中极为罕见。本文报道 1例发生于舌下腺的腺样囊性癌在多形性腺瘤的病例。     

Carcinoma ex pleomorphic adenoma of the buccal region is composed of salivary duct carcinoma and squamous cell carcinoma components

A 73-year-old female presented with an asymptomatic mass in the left buccal region that she had first noticed 4 years earlier. The tumor, which was located in the buccal space, was clinically diagnosed as a salivary gland tumor and treated by excision. Histopathological examination revealed a capsule of connective tissue consisting of three different histopathological neoplastic areas in a large, fibrous, hyalinizing stromal background. The neoplastic lesion contained two malignant and one benign element, with histological characteristics consistent with squamous cell carcinoma (SCC), salivary duct carcinoma (SDC) and pleomorphic adenoma (PA). The SCC nests showed no continuity with the buccal mucosa. Both the SCC and SDC nests were surrounded by non-atypical myoepithelial cells, suggesting that both components may have developed from transformation of metaplastic luminal epithelial cells of PA. The tumor was diagnosed as a non-invasive carcinoma (SCC and SDC) ex pleomorphic adenoma (Ca-ex-PA). There was no evidence of recurrence 16 months after operation.     

Neural adhesion molecule (N-CAM) in pleomorphic adenoma and carcinoma ex-pleomorphic adenoma

BACKGROUND: The neural cell adhesion molecule (N-CAM) has been implicated in the behaviour of the adenoid cystic carcinoma. In vitro, it was demonstrated that N-CAM inhibits cell invasion. The aim of this study was to search for N-CAM in the most common salivary gland tumour that has a malignant counterpart. METHODS: We investigated the presence of N-CAM in pleomorphic adenoma and its malignant counterpart, the carcinoma ex-pleomorphic adenoma, using the immunohistochemistry technique. RESULTS: Neural cell adhesion molecule was expressed in all cases of pleomorphic adenoma, strongly labelling the luminal cells of the double-layered ductform structures. This expression was weaker in neoplastic myoepithelial cells and progressively diminished at a distance from the luminal cells. In carcinoma, ex-pleomorphic adenoma N-CAM was either totally absent or faintly present at the apical pole of the few luminal cells. CONCLUSIONS: As a result of the peculiar distribution of N-CAM in pleomorphic adenoma, we speculated that N-CAM behaves as a tumour-suppressor molecule, which is expressed in the benign neoplasm and which is down-regulated after malignancy, when the tumour assumes an invasive behaviour.     

Myxolipomatous pleomorphic adenoma: an unusual oral presentation

The first case of a myxoid variant of lipomatous pleomorphic adenoma arising in the intraoral minor salivary gland is presented. A well-encapsulated tumor was composed almost entirely of myxolipomatous tissue with honeycomb-like spindled cellular areas, which contained only a scant glandular element. Immunohistochemistry confirmed the myoepithelial nature of spindle cells intimately admixed with mucoadipose component. We propose the term myxolipomatous pleomorphic adenoma for this peculiar lesion.     

Immunohistochemical study of four histologic types of parotid gland pleomorphic adenoma

The immunohistochemical detection of lysozyme, lactoferrin, a1-antichymotrypsin and a1-antitrypsin was used to investigate the marker expression and histogenesis of each one of four histologic types of 20 parotid gland pleomorphic adenomas. Moreover, 10 adult and 20 neonate parotid glands were studied. The immunohistochemical analysis revealed that tumor types 1 and 2 are nearly identical immunohistochemically while types 3 and 4 differ from one another, as well as from types 1 and 2. The markers used failed to suggest that the tumor arises from epithelial cells of any specific anatomic part of the parotid gland.     

Immunohistochemical evaluation of the small and large proteoglycans in pleomorphic adenoma of salivary glands

This study investigated the immunolocalization of small and large proteoglycans (PGs), including decorin, biglycan, PG-M/versican and aggrecan, in salivary pleomorphic adenoma (PA) using monoclonal and polyclonal antibodies. In addition, a polyclonal antibody, A0082, recognizing blood vessels was also used to help identify truly mesenchymal tissues in PA. Decorin reactivity was detected only in tumor capsule and interstitial tissue of non-neoplastic salivary gland, but not in the tumor tissue. Biglycan was frequently revealed throughout the matrix of small chondroid regions and in the peripheral portion of larger chondroid regions. PG-M/versican was mainly localized to the truly mesenchymal tissues in PA and the innermost portion of tumor capsule. On the contrary, aggrecan was extensively expressed in the non-luminal epithelial areas as well as in the myxoid and chondroid areas, but not in the truly mesenchymal tissues. These findings suggest that aggrecan is the most widely distributed PG in PA and may be produced mainly by non-luminal tumor cells. The absence of aggrecan from the truly mesenchymal tissues argues against its origin from this source. Both aggrecan and biglycan may play important roles in the chondroid differentiation and morphogenesis of PA.     

Precancerous foci in pleomorphic adenoma of the salivary gland: recognition of focal carcinoma and atypical tumor cells by P53 immunohistochemistry

BACKGROUND: It is still controversial if atypical tumor cells scattered in salivary pleomorphic adenomas are precancerous and how carcinoma arises in pleomorphic adenomas. METHODS: We studied clinicopathologically the frequency and variation of cellular atypia among tumor cells and examined the expression status of p53 gene products as well as proliferating cell nuclear antigen (PCNA) in 101 surgical materials of pleomorphic adenomas. RESULTS: Histopathologically, atypical tumor cells were found in 51% of the cases examined. Their mode of distribution was classified into three groups: focal (six cases, 6%) which could be identified as focal carcinoma, measuring less than 1 mm in diameter; sporadic (15 cases, 15%) and singular (30 cases, 30%). These atypical cells were located mainly within sheet-like nests of tumor cells but not in chondroid or fibro-hyaline foci. Immunohistochemically, most of the atypical cells were positive for p53 gene products and PCNA. CONCLUSION: The results indicated that atypical cells with p53 protein accumulation in their nuclei could be regarded as cells in a precancerous state not yet forming an apparent carcinomatous nest. Some cell population with these atypical cells are likely to form focal carcinomas and then to an apparent form of carcinoma in pleomorphic adenoma.     

Immunolocalisation of cartilage-derived retinoic acid-sensitive protein in pleomorphic adenoma of the parotid salivary gland

Pleomorphic adenoma of the parotid salivary glands often contains chondroid elements and may exhibit cartilaginous and osseous differentiation, although the latter is extremely rare. Twenty-nine pleomorphic adenomas (PAs) of the parotid gland were examined immunohistochemically for the distribution of cartilage-derived retinoic acid-sensitive protein (CD-RAP), a recently described marker of chondrocytes, which may be important in the morphogenesis and development of the salivary gland. In the normal parotid gland, the ductal cells expressed CD-RAP, but not the myoepithelial cells. In the pleomorphic salivary adenomas, the duct-like cells, but not the myoepithelial cells, expressed CD-RAP. Since many authorities consider myoepithelial cells to be the source of the chondroid matrix, it is surprising that these cells do not express the chondrocytic marker, CD-RAP. Putative neoplastic myoepithelium in the pleomorphic adenoma and some cells in the myxochondroid areas expressed S-100 and calponin.     

Localization of glycosaminoglycans (GAGs) in pleomorphic adenoma (PA) of salivary glands: an immunohistochemical and histochemical evaluation

The tumor matrix of salivary pleomorphic adenoma (PA) is characteristically rich in glycosaminoglycans (GAGs), which contribute to its complex histoarchitecture. This study evaluated the microscopic localization of various GAGs in 17 PAs, using a panel of anti-GAG monoclonal antibodies and biotinylated hyaluronic acid (HA)-binding protein. Both epithelial and mesenchymal-like tissues were confirmed to contain GAGs. Luminal epithelial cells mostly lacked GAGs, whereas GAGs were seen both in the cytoplasm and cell membrane of non-luminal epithelial cells. In addition, small intercellular accumulations of GAGs were often present in solid epithelial areas, implying the epithelial origin of GAGs. GAGs did not appear to be a main component of the hyaline matrix. The myxoid region was consistently stained for both chondroitin 6-sulfate (CS-6) and HA but variably for chondroitin 4-sulfate (CS-4), dermatan sulfate (DS) and keratan sulfate (KS); heparan sulfate (HS) was not detected. The chondroid region showed increased staining for CS-6 but reduced staining for HA when compared with the myxoid region. In addition, CS-4, DS and KS were seen both in chondroid cells and the territorial matrix, whereas HS was present only in the cells. It is suggested that GAGs in PA are mainly produced by non-luminal cells and influence the proliferation, differentiation, secretory activity and shape of tumor cells, thus contributing to the morphological diversity of this tumor.     

Immunohistochemical demonstration of bone morphogenetic protein-2 and type II collagen in pleomorphic adenoma of salivary glands

Immunohistochemical investigation of bone morphogenetic protein-2 (BMP-2) and type II collagen, two cartilage-associated proteins, was undertaken using monoclonal antibodies in 20 cases of salivary pleomorphic adenoma (PA) in order to explore their possible roles in chondroid differentiation of this tumor. Other salivary gland tumors, including adenoid cystic carcinoma (17 cases), polymorphous low-grade adenocarcinoma (10 cases), basal cell adenoma (3 cases), basal cell adenocarcinoma (1 case), and epithelial-myoepithelial carcinoma (2 cases), were also examined for comparison. In PA, BMP-2 immunoreactivity was detected in the luminal and non-luminal cells of the tubulo-ductal structures, plasmacytoid cells, and other scattered tumor cells in solid areas. In addition, tumor cells in chondroid areas in most cases (14/15), and stellate cells in myxoid areas in many cases (7/19), were also intensely labeled for BMP-2. Furthermore, BMP-2 was also detected in the non-neoplastic ductal cells in salivary glands, whereas no other salivary gland tumors were positively stained for this protein. Type II collagen was localized in the intercellular matrix of chondroid areas and in a few chondroid differentiating cells in myxoid areas, confirming its cartilage-specificity. A proportional relationship was observed between BMP-2 expression and chondroid formation, although BMP-2 was also stained in occasional PAs without chondroid formation. It is speculated that BMP-2 might be secreted by tumor cells and play a role in chondroid formation in PA by inducing some tumor cells to produce type II collagen and other chondroid matrical substances, like glycosaminoglycans. The expression of BMP-2 is specific to PA and may possibly be used as a useful marker in differentiating PA from other salivary gland tumors.     

Biosynthesis of glycosaminoglycans and aggrecan by tumor cells in salivary pleomorphic adenoma: ultrastructural evidence

The present study attempted to discover the sites of synthesis of various glycosaminoglycans (GAGs) and aggrecan in salivary pleomorphic adenoma (PA) with the use of a highly sensitive and specific post-embedding immunogold-silver staining technique at the ultrastructural level. Silver particles representing various GAGs and aggrecan were found to accumulate frequently in the intercellular spaces of non-luminal cells in the epithelial clusters and were dispersed in the myxoid matrix of the mesenchyme-like areas. Furthermore, the non-luminal epithelial cells were demonstrated to contain immunopositive intracytoplasmic vesicles and vacuoles, some of which were of Golgi complex origin. In contrast, intracellular silver particles for hyaluronic acid were mostly attached to the inner surface of the cell membrane. These observations agree well with the current theories of the biosynthesis of GAGs and proteoglycans and provide direct evidence for the production of various GAGs and aggrecan by tumor epithelial cells of PA. Such findings support the ideas that in PA a loss of epithelium occurs by stromalization following epithelial secretion of extracellular matrix substances and transformation of epithelium to mesenchyme represents the basic principle of the tissue heterogeneity in this tumor.     

Quantitation and localization of cycling tumor cells in pleomorphic adenomas and myoepitheliomas: an immunohistochemical analysis

Previous investigations have suggested that in certain salivary gland tumors only nonluminal (myoepithelial-like) tumor cells proliferate and that this may have histogenetic implications; however, no quantitative assessment of the cycling component is available. We decided, therefore, to enumerate the cycling luminal and nonluminal cells in 15 pleomorphic adenomas and six myoepitheliomas by using an antibody to proliferating cell nuclear antigen. The mean percentages of cycling luminal and nonluminal cells in pleomorphic adenomas were 2.3±1.4 and 2.4±2.3. respectively, and 2.1 ±0.7 of the tumor cells in myoepitheliomas. Even though duct-like structures in pleomorphic adenomas are considerably separated by more numerous nonluminal cells and. therefore, cycling cells may seem fewer, both cell types proliferate at similar rates. The results indicate that nonluminal cells are not the sole proliferative component in salivary gland tumors.     

Synthesis of elastin by pleomorphic adenomas

Previous morphologic and histochemical studies have documented extracellular elastin and elastic fibers within the matrix of pleomorphic adenomas of the salivary glands. By morphologic criteria, the elastin appeared to be synthesized by the tumor rather than being a consequence of stroma produced in response to the tumor cells. To examine this issue, nine pleomorphic adenomas were studied by immunohistochemistry and in situ hybridization with tropoelastin-specific antibodies and complementary DNAs. Corroborating the previous morphologic studies, immunohistochemistry demonstrated abundant extracellular elastin within the matrix of pleomorphic adenomas. Additionally, both immunohistochemistry and in situ hybridization demonstrated continued synthesis of tropoelastin by the neoplastic cells. Tropoelastin production was seen in neoplastic cells with all morphologies.     

腮腺区复发性多形性腺瘤恶变侵犯颧骨1例报告

腮腺区复发性多形性腺瘤（recurrent pleomorphic adenoma,RPA）存在一定的恶变几率,但检索国内外文献未见侵犯颧骨的报道。本文报告1例腮腺区复发性多形性腺瘤恶变侵犯颧骨病例,并结合相关文献分析其临床、影像及病理特点,以进一步提高对该病的认识,减少误诊误治。