The present biological profile of the adenomatoid odontogenic tumour represents an updating of the data published by the authors from 1990 to 1996. Several new facets of this tumour appear from the approximately 250 cases having been published in recent years. Papers on peripheral variants, AOT-CEOT combined lesions, pigmented AOTs, cases exhibiting tubular dentin induction, new immunohistochemical and ultrastructural data are among the findings having increased our understanding of this interesting tumourous growth. However, the present updating did not in any way change our conception of the unique clinical, radiographical and histological features of the AOT but rather totally confirmed it.

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Classification of ameloblastoma into solid or multicystic, unicystic and peripheral types based on the biological behavior has gained recent recognition. Available English-language literature on unicystic ameloblastoma since its first description in 1977 was reviewed. A total number of 182 cases was retrieved to evaluate various clinical and pathological aspects of this variant. The tumor tends to occur at an younger age (mean: 25.5 years) and exhibits a low rate of recurrence (13.8%) following enucleation or curettage in comparison to the conventional ameloblastoma. The variability of histological spectrum, diagnostic problems and choice of treatment for this form of ameloblastoma were also discussed in the light of recent research interest and progress.

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We studied quantitatively differences in consistency of normal gingiva, gingiva affected with squamous cell carcinoma, and that with leukoplakia to evaluate its potential for the preoperative diagnosis of gingival carcinoma. Twenty-nine patients with gingival squamous cell carcinoma, 24 with leukoplakia, and 120 with normal gingiva were examined using an instrument capable of measuring consistency as a function of the load (in grams) needed to displace gingiva by 1.0mm by a probe 1.0mm in diameter. The mean values of consistency in normal gingiva were 67.9±4.8g, 68.1±4.3g, 59.7±4.6g, and 67.4±4.2g, corresponding to the maxillary labial, maxillary buccal, mandibular labial, and mandibular buccal, respectively. The mean value of consistency in gingival carcinoma and leukoplakia was 24.5±3.3g, and 52.4±7.1g, respectively. Differences in consistency among gingival carcinoma, leukoplakia, and normal gingiva were significant (p<0.001). It was concluded that the consistency in gingival lesions was objectively and quantitatively evaluated by this instrument.

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The present study was carried out to investigate histologically, immunohistochemically and ultrastructurally the effects of Trp-P-2 applications together with excisional wounding of hamster tongues. Histologically the animals which received Trp-P-2 treatment in combination with excisional wounding developed epithelial dysplasias in their tongues. Immunohistochemically the cells of these epithelial dysplasias stained positive for papillomavirus genusspecific antigen. Furthermore, ultrastructurally these dysplastic cells exhibited the presence of virus-like particles within their nuclei. In the present study, it seemed obvious that epithelial dysplasia was induced by excisional wounding and Trp-P-2 treatment, but the relationship between the appearance of epithelial dysplasia and the presence of virus-like particles was not clear.

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Expressions of laminin and matrix metalloproteinases (MMPs) were investigated in metastatic and non-metastatic cells isolated from an experimental model of lymph node metastasis (O-1N). By Northern blot analysis, the metastatic cells expressed mRNA for laminin 6 days after plating, whereas the expression was very weak in the non-metastatic cells at the same stage. Immunohistochemical signals for laminin observed initially in the cytoplasm gradually increased in intensity and number with time and showed a honeycomb-like meshwork pattern at 7 days in both cells. The 92kD gelatinolytic activity (MMP-9) on zymography was stronger in the metastatic cells than in the non-metastatic cells. The 72kD band (MMP-2) was detected equally in both cells. The 59kD and 56kD caseinolytic activities (MMP-3) were observed only in the metastatic cells. The results indicate that the enhanced gene transcription and biosynthesis of laminin and concordant active destruction of basement membrane by MMPs in the metastatic cells may be involved in the process of lymph node metastasis in O-1N.

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A rare case of salivary duct carcinoma with sebaceous cell differentiation arising in the parotid gland of a 78-year-old man was studied. The tumor consisted of large polyhedral cells with pale eosinophilic clear cytoplasms in which many vesicles were included. These tumor cells were arranged in a sheet-like appearance forming cellular nests separated by prominent fibrous stroma. Comedo-type central necrosis and cyst- or duct-like spaces were observed in the nests. The latter histogical feature resulted in the cribriform appearance. Papillary proliferation was co-existent in a small part of the tumor tissue. Considerable number of oil red O- and Sudan III-positive sebaceous cells were observed in the tumor tissue. Electron microscopic observations revealed a number of intracytoplasmic vesicles which were thought to be fat droplets. Based upon these histological features, the present case was diagnosed as salivary duct carcinoma with sebaceous cell differentiation. Immunohistochemical staining for the epithelial membrane antigen and the actin suggested that the salivary duct carcinoma originated in the epithelial cell of the intercalated. However, this issue is still open to question.

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Deletion of the terminal q segment of chromosome 4 is a quite rare karyotype of newborns with multiple malformations. In our case, the facial appearance was unusual due to hypertelorism with epicanthal folds, depressed nasal septum, bilateral cleft lip and palate, micrognathia and low-set ears. Limb malformations were not seen. Bilateral inguinal hernia was detected at birth. We report a case of cleft lip and palate associated with 4q terminal deletion syndrome and a review of the literature.

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This report describes a case of desmoplastic fibroma of the maxilla, for which the differential diagnosis and surgical treatment of choice are discussed in brief.

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