Non-calcifying Pindborg tumor with Langerhans cells

A rare case of calcifying epithelial odontogenic tumor (CEOT) devoid of calcification is reported with histochemical, immunohistochemical and electron microscopic studies. The tumor occurred intraosseously in the left maxillary canine and premolar region of a 58-year-old man. The tumor chiefly consisted of scattered small islands of epithelial cells in an abundant fibro-myxoid connective tissue stroma. Among the nests, there were many spherical bodies of eosinophilic substance for which non-AA amyloid and non-keratin or basal lamina-like natures were demonstrated histochemically and immunohistochemically. In some nests, there were a few, occasionally several, cells positive for S-100 protein. Ultrastructurally, Langerhans cells with indented nuclei and Birbeck's granules were seen among tumor cells. The prognostic significance of the paucity of calcification and the presence of Langerhans cells in CEOT of which this is only the second description is discussed.

Verruciform xanthoma of the oral mucosa: a clinicopathological study with immunohistochemical findings relating to pathogenesis

Verruciform xanthoma is an uncommon benign lesion with unknown aetiology and pathogenesis. In this study, we report ten cases of verruciform xanthoma and document their clinical and histopathological findings. An immunohistochemical investigation was performed using antibodies to macrophage, leukocyte common antigen, T lymphocytes, B lymphocytes, S-100 protein, lysozyme and alpha-1-antichymotrypsin. Our results were similar to the other reported cases. Eighty percent of our cases were found on the gingiva. Candidal hyphae were found in the superficial parakeratotic layers in five cases. The clinical diagnosis of the lesion ranged between papilloma and squamous cell carcinoma. It is important for clinicians to take into consideration the possibility of verruciform xanthoma in the differential diagnosis of papillary and granular lesions of oral mucosa. Immunohistochemically, all foam cells were strongly stained with antimacrophage antibodies. T lymphocytes were the predominant infiltrating lymphocytes in the lesion. Langerhans cells in the epithelia were fewer than those in corresponding normal tissue. Our immunohistochemical findings suggest that verruciform xanthoma is may be a local immunological disorder, with a cell mediated mechanism.

Intraductal papilloma of the anterior lingual salivary gland. Case report and immunohistochemical study

A case of intraductal papilloma occurring in the anterior lingual salivary gland (Blandin-Nuhn's gland) of a 58-year-old woman is presented. This location has not been reported previously. The results of histologic and immunohistochemical studies point to an epithelial origin of excretory salivary gland ducts and also demonstrate the secretory potential of the tumor cells.

Jaw cysts with orthokeratinization: analysis of 12 cases

The clinico-pathologic, immunohistochemical and radiological features of 12 jaw cysts with a prominent orthokeratinized epithelial lining were studied and compared with those of typical odontogenic keratocysts and dentigerous cysts. They differed significantly from odontogenic keratocysts in terms of biologic behavior and histopathologic findings. Although immunohistochemical staining of the epithelial linings for cytokeratins, EMA, CEA and involucrin has not shed any light on the histogenesis of these lesions, staining patterns for these markers were significantly different from those of odontogenic keratocysts and non-keratinized dentigerous cysts. Radiologically, nine cases appeared as dentigerous cysts; two cases, one with sebaceous differentiation, as non-dentigerous unilocular cysts, and the remaining one was exceptional as it showed multiple epidermal cysts with prominent dermal appendages histologically. It is suggested that most of the orthokeratinized jaw cysts may belong to clinico-pathological entities different from odontogenic keratocysts with the majority representing dentigerous cysts with orthokeratinization. The possibility of the existence of rare central dermoid or epidermoid cysts is also to be considered.

Effect of exogenously applied prostaglandin E2 on alveolar bone loss--histometric analysis

The effect of prostaglandin E2 (PGE2) on alveolar bone resorption was examined in 8-week old Wistar rats by histometric analysis. One mg/ml PGE2 topically applied to gingival sulcus induced a marked increase in osteoclasts. The number of osteoclasts increased progressively and reached a maximum at 12 hours. Ultrastructurally, these osteoclasts were in active form with well developed ruffled borders and clear zones. The changes in numbers of osteoclasts after application of various concentrations of PGE2 were dose-dependent (0.001 to 1.0 mg/ml), but higher concentrations of PGE2 (2 mg/ml) were less effective. In addition, the number of osteoclasts in groups treated with both PGE2 and endotoxin was higher than those that received PGE2 only. These results indicate that bone resorption caused by PGE2 depends on activation and increase of osteoclasts, and suggests that endogenous PGE2 production by host cells stimulated by plaque-associated bacterial endotoxin may be an important pathogenetic factor in periodontal disease.

Enhanced collagen phagocytosis by rat molar periodontal fibroblasts after topical application of lipopolysaccharide--ultrastructural observations and morphometric analysis

To investigate the effect of lipopolysaccharide (LPS) on phagocytic activity of collagen fibrils by periodontal fibroblasts, we studied rat molar gingival connective tissue and periodontal ligament under light and electron microscopy after topical application of LPS (5 mg/ml in physiological salt solution (PS)) on the gingival sulcus. Phagocytic activity of collagen fibrils by fibroblasts was evaluated by counting the number of collagen-containing vacuoles inside fibroblasts that were present within a defined area (1200 microns2). Values obtained from fibroblasts in the subepithelial connective tissue, the region near the alveolar crest, and the middle region of periodontal tissue were compared. Periodontal ligament fibroblasts showed increased phagocytosis of the collagen fibrils from 3 hours to 1 day after topical LPS application, but no differences were observed in the gingival tissue. The intracytoplasmic vacuoles containing collagen fibrils were of various sizes and shapes, showing positive for acid phosphatase and/or alkaline phosphatase reaction. Collagen phagocytic activity of the fibroblasts in the middle region of the periodontal ligament also increased after PS treatment. However, this was significantly less than that observed in LPS-treated animals (p less than 0.01). This study indicates that LPS may enhance the degradation of collagen by stimulating the phagocytic activity of the periodontal ligament fibroblasts.

Clear cell tumors of minor salivary gland origin. An immunohistochemical and ultrastructural analysis

Three cases of monophasic glycogen-rich clear cell tumors of palatal gland origin were examined immunohistochemically and ultrastructurally in attempts to characterize their cellular composition. Despite their histologic resemblances, the clear cells from each case showed different immunohistochemical features. In case 1 the extensive positivity for vimentin and S-100 protein, in addition to the focal expression of actin and glial fibrillary acidic protein, strongly suggested that the clear cells were myoepithelial in nature. In contrast, the clear cells from case 2 exhibited both keratin and epithelial membrane antigen positivity, as well as ultrastructural features that suggested that they were glandular epithelial in nature. In case 3 no special markers except for keratin could be detected, indicating the less differentiated nature of the clear cells. These results show the heterogeneity of the clear cell tumor group of minor salivary glands.

Spindle cell squamous carcinoma of the oral region. An immunohistochemical and ultrastructural study on the histogenesis and differential diagnosis with a clinicopathological analysis of six cases

Six cases of spindle cell squamous carcinoma (SCSC) of the oral cavity were studied clinicopathologically, immunohistochemically and ultrastructurally to summarize the clinicopathological features of this rare neoplasm and to discuss the debatable histogenesis of the sarcomatoid component and the differential diagnosis of SCSC. The mean age of the patients was 72 years and the female to male ratio was 1:2. Four of them had a history of irradiation for pre-existing squamous cell carcinoma. One patient died of SCSC. While clinical and histological prognostic factors of SCSC could not be determined, it was shown that radical surgery resulted in good prognosis. The epithelial nature of the sarcomatoid component of SCSC was clearly revealed by a combination of immunohistochemical staining for keratins and electron microscopic demonstration of tonofilament-like filaments and/or desmosome-like structures. Together with electron microscopic evaluation of the tumour cells, immunohistochemical characterization of tumour cells using antibodies to keratin, vimentin, glial fibrillary acidic protein and S-100 protein is very helpful in differentiating SCSC from true spindle cell sarcoma, melanoma and malignant myoepithelioma. In the immunohistochemical differential diagnosis of SCSC, it is important to remember that SCSC should not be ruled out of the differential diagnosis by a positive reaction for vimentin in sarcomatoid tumour cells. Absence of staining for keratin in the sarcomatoid tumour cells does not always exclude SCSC, because some SCSCs show immunoreactivity of keratin in their sarcomatoid components only with some anti-keratin antibodies. Different kinds of anti-keratin antibodies should be applied in the differential diagnosis of SCSC.

The cellular composition of basal cell adenoma of the parotid gland: an immunohistochemical analysis

Four cases of basal cell adenoma of the parotid gland were examined immunohistochemically to characterize their cellular composition. In all cases epithelial membrane antigen and keratin were detected in the inner luminal cells; some cells also showed positive staining for secretory functional markers, indicating their differentiation toward secretory epithelium. In tubular and trabecular types the outer cells consistently displayed an intense staining for vimentin and some were also positive for actin, indicating their myoepithelial nature. In the solid type, most tumor cells resembled the ductal cells or basal cells of larger ducts in normal gland with regard to their immunoreactivity. Our results may suggest that the proportion and arrangement of heterogeneous tumor cells are responsible for different histologic patterns of the salivary basal cell adenoma.

Ultrastructural and immunohistochemical observations of a true malignant mixed tumor (carcinosarcoma) of the tongue

True malignant mixed tumor (TMMT) of salivary glands, with both carcinomatous and sarcomatous components, is exceedingly rare. We offer a case of TMMT in a 79-yr-old man, which may represent the first report example of this unusual neoplasm arising in the tongue. The carcinomatous component was mainly of solid basaloid carcinoma with focal glandular differentiation, while the sarcomatous component was composed of pleomorphic elements such as chondrosarcoma, myxosarcoma and fibrosarcoma. Carcinoma cells at the periphery of solid nests occasionally merged into these sarcomatous elements. Immunohistochemically, basaloid carcinoma cells showed positive reaction for both low molecular weight cytokeratin and S-100 protein, whereas carcinoma cells lining ductal spaces were positive for a wide spectrum of keratin and EMA. The sarcomatous elements revealed the presence of vimentin and S-100 protein. Ultrastructurally, basal lamina-like material and/or mucoid precipitates often accumulated separating the tumor cells from each other singly or into a few cell group. Some sarcomatous cells assumed the myoepithelial features, such as the presence of microfilament bundles with dense bodies and pinocytotic vesicles along the cell periphery. These findings may indicate that TMMT shares a common histogenesis with pleomorphic adenoma.

Lectin binding of rat gingival epithelia

Oral gingival epithelium (OGE), oral sulcular epithelium (OSE) and junctional epithelium (JE) were examined histochemically by using different lectins as markers for epithelial differentiation. The staining pattern of gingival epithelia was compared with that of the buccal and palatal epithelia. Binding of WGA had a uniform distribution in all the epithelia examined. A positive reaction was found in all the basal and spinous layers, but not in the cornified layer of the epithelia. BPA binding was seen in the lower spinous layer of OGE, OSE, buccal and palatal epithelia, and in most of the JE. The basal layer and the cells directly attached to the tooth surface at the apical part of JE were nonreactive with BPA. GS-I reacted with the basal and suprabasal layers of each epithelium and with the cells attached to the tooth at the apical part of JE. UEA-I reacted with the upper spinous layer of OGE, OSE and epithelia of hard palate, but not with any of the cells of the JE. Our results agree with previous data suggesting that OGE and OSE exhibit squamous differentiation similar to that of the masticatory epithelium of hard palate. Furthermore, our results suggested that the JE cells undergo differentiation equivalent to that of the suprabasal and lower spinous cells of OGE. The cells along the tooth surface at the apical part of JE, however, form a distinct population of cells with basal nature.

Penetration and uptake of colloidal gold-labeled concanavalin A in the junctional epithelium of the rat

A complex of colloidal gold and concanavalin A (CG-Con A) with various biological properties and high ultrastructural resolution was applied into the sulcus of rat molar gingiva and traced with an electron microscope for three hours to examine the cytological changes occurring in the cells of the junctional epithelium (JE) during penetration of extrinsic irritants, and to determine the roles of JE cells in such a circumstance. While the penetration of CG-Con A was impeded on the surface of keratinized oral gingival/sulcular epithelium, CG-Con A penetrated swiftly through JE into the connective tissue. In the process of penetration, CG-Con A was taken up by lysosomal and vacuolar structures of JE cells in which degenerative changes were often provoked. Degeneration of JE cells was seen selectively in the second and/or third cell layers from the innermost cell layer of JE. It was assumed that JE cells by their phagocytic activity might participate in the first line of defense against extrinsic irritants. On the other hand, the phagocytic activity of JE cells seems also to be involved in tissue destruction, if the amount and/or toxicity of irritants exceed the dissimilating capacity of JE cells.

Light and electron microscopic studies of experimentally-induced pathologic changes in the rat periodontal tissue

Morphological changes in periodontal tissues following topical application of lipopolysaccharide (LPS) or prostaglandin E2 (PGE2) were examined in Wistar rats by light and electron microscopy. Ultrastructural demonstration of acid phosphatase and immunohistochemical localization of lysozyme in these tissues were also studied. The number of osteoclasts along the alveolar bone facing the periodontal ligament was counted.

After topical application of LPS, degeneration and necrosis of the junctional epithelial cells, gingival fibroblasts, and alveolar osteoblasts were observed, as were increased bone resorption by osteoclasts and enhanced phagocytosis of collagen fibrils by fibroblasts. LPS appears to traverse easily through the junctional epithelium into the underlying gingival connective tissues. There it can cause destruction of deeper periodontal tissues by activating alveolar bone resorption and by enhancing the phagocytosis of collagen fibrils. PGE2 topically applied induced similar morphological changes. Possible participation of PGE2 in the induction of these LPS-related changes is discussed.

Ultrastructure of regenerated junctional epithelium after surgery of the rat molar gingiva

To elucidate the ultrastructure of reconstructed dentogingival junction and cytological details of regenerated junctional epithelium (RJE) and to discuss the functional aspects of RJE through comparing its fine structure with normal structure, molar gingivae of 15 Wistar rats were examined by electron microscopy at 6, 8 and 12 weeks after electrosurgical gingivectomy. As early as 6 weeks after surgery, the epithelial architecture of dentogingival junction was reestablished at the light microscopic level, and RJE showed the ultrastructure indistinguishable from that before surgery. The cytoplasmic vacuoles, characteristic of rat JE, displayed the morphology, distribution and intimate relationship with lysosomes, all of which were quite identical to those in controls, and were regarded to represent "phagosomes." Since various findings specific to JE are apparently reproduced in RJE, it seems that those peculiar structures would be an expression due to the environment rather than to the predetermined nature. RJE also might play a defensive function through the endocytic-vacuolar system as suggested for normal JE. The presence of two types of cuticular structures, which were not conspicuous in normal JE, was also revealed between RJE and the tooth.

Histologic evaluation of myoepithelial participation in salivary gland tumors

To evaluate the myoepithelial participation in various salivary gland tumors, 40 cases were studied using the tannic acid--phosphomolybdic acid--Levanol fast cyanine 5RN (TPL) method directly correlated with ultrastructural observation. The TPL positivity corresponded to cytofilaments, especially microfilaments within the cells showing myoepithelial features. This approach allowed categorization of the examined tumor types into the following 4 groups according to the degree of myoepithelial participation: tumors with major myoepithelial, epithelial-myoepithelial (biphasic), minor myoepithelial, and no myoepithelial participation. It is suggested that the first 2 categories form a spectrum with myoepithelioma and basal cell adenoma at the extremes, in which neoplastic myoepithelial cells assume an active and integral constitutive rôle. The present findings indicate that the TPL method offers a very reliable marker for the screening of neoplastic myoepithelium in salivary gland tumors and thus may help in subclassification on a histogenetic basis for these tumors.

Ultrastructural cytochemical demonstration of elastin in the matrix of salivary gland tumors

Following light microscopic survey of the incidence of elastic tissue in 80 salivary gland tumors, tissue samples from 14 pleomorphic adenomas, three myoepitheliomas, and eight adenoid cystic carcinomas were processed for cytochemical demonstration of elastin with the tannic acid stain for ultra-thin sections. For comparative study, some other tumor types devoid of elastic tissue at the light microscopic level and non-neoplastic submandibular glands were also investigated. Elastic deposits of varying amounts were clearly revealed on the basal-lamina-like material and/or masses of microfibrils in the matrix close to the neoplastic myoepithelium and, to a lesser degree, immediately beneath the non-neoplastic myoepithelium. None of the other tumor types without myoepithelial differentiation contained elastic deposits closely associated with the neoplastic cells. Intimate topographical relationship of such as immature elastic fiber or developing elastic tissue to the neoplastic myoepithelial cells strongly indicated the primary origin of elastic components from these cells. It is postulated that the potential of salivary tumor cells to produce elastin is regarded as an indicator of their myoepithelial nature or differentiation.