Cementoblastoma is a relatively rare type of odontogenic tumor. This study investigated the features of cementoblastoma tumor cells in three cases using immunohistochemistry. Immunopositive reactivity for Ki-67 was recognized in the nuclei of spindle-shaped cells that were located in the fibrous connective tissue among the cementum-like hard tissue. Those cells were mainly discernible at the periphery of the tumors. Polygonal cementoblast-like cells with large nuclei surrounding the hard tissue were immunopositive for osteopontin and osteocalcin but not for Ki-67, which suggests that these cells may be more differentiated cells that have the potential to form hard tissue.

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Epstein-Barr virus (EBV) is a ubiquitous human herpes virus that infects over 90% of the adult human population of the world. Although association of EBV with Burkitt's lymphoma and nasopharyngeal carcinoma is well established, reports on the association of EBV with oral squamous cell carcinoma (OSCC) are inconclusive. To find out expression pattern of EBV genes in OSCC, we isolated wild type EBV infected OSCC cell lines by co-culture and limiting dilution techniques, and investigated the latent gene expression pattern of EBV in these cell lines. EBV nuclear antigen (EBNA)-1 protein was detected by indirect immunofluorescence in all of the infected cell lines. EBV encoded small RNA (EBER)-1, Cp/Wp-initiated EBNA-1, EBNA-2, latent membrane protein (LMP)-1 and BamHI-A rightward open reading frame (BARF0) gene expression were detected in isolated OSCC cells by RT-PCR and Southern blot hybridization. However, LMP-2A and -2B expression were not detected. The latent gene expression pattern was similar to those in undifferentiated nasopharyngeal carcinoma and Hodgkin's disease (i.e., type II latency of EBV). This is the first report concerning successful infection of wild type EBV to OSCC cells. These results could bring about a better understanding of the influence of EBV on OSCC cells.

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Multiple myeloma (MM) is a plasma cell malignancy. Low proliferative activity of myeloma cells makes it difficult to perform the cytogenetic analyses. By comparative genomic hybridization (CGH), we detected a large number of chromosomal gains and losses in 3 sister myeloma cell lines (CLs), KMS-12BM/PE pair, KMS-21BM/PE pair, and KMS-28BM/PE pair, that were established from bone marrow (BM) and pleural effusion (PE) cells obtained from the same patient. The most recurrent gains were 1q, 11q and 18q, whereas the most recurrent losses were 9p, 16q, 17p and 22q. The smallest region of overlap (SRO) among the BM-origin CLs and the PE-origin CLs was identified. In the SRO, we deduced a candidate gene, such as IL6R, cyclin D1, BCL2, B7H1, p53, IRS 1, c-MYC, TNFSF8, and cadherin family genes, the amplification or deletion of which might be associated with disease progression, cell proliferation, transmigration and/or infiltration.

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We experienced a case of epithelioid hemangioendothelioma that occurred in the maxilla of a 50-year-old woman. The incidence of this disease is high in soft tissue and bones, and its development in the oral cavity has rarely been reported. The patient visited our hospital because of an asymptomatic tumor in the buccal-side gingiva. Under the diagnosis of oral benign tumor, we excised the lesion. Histopathologically the tumor had multiple alveolar structures built up of spindle cells with egg-shaped nuclei. The alveolar structures had small lumina in their central part, and hemocyte components were observed in some of them. Immunohistochemically, the tumor cells were positive for Factor VIII related antigen. Electronmicroscopy revealed micropinocytotic vesicles and multivesicular bodies. On the basis of these findings, we made a diagnosis of epithelioid hemangioendothelioma. There are clinical and histological differences between epithelioid hemangioendothelioma of the oral cavity and the other site.

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A case of intraosseous schwannoma of the mandible is presented. This tumor was so large that expansion of the lingual cortex of the alveolar bone led to perforation. It was linked with the inferior alveolar nerve in the distal side and the mental nerve in the mesial side, and therefore the nerve was severed and electrocoagulated. Histopathologically, the tumor showed characteristics of a schwannoma, with a mixture of Antoni- A and -B areas. Atypical cells and degeneration were also seen. The defect of the mandibular bone after enucleation of the tumor was filled with a mixture of iliac cancellous bone marrow and hydroxyapatite granules. There has been no sign of recurrence of this tumor for nine years since the operation.

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A case of symmetric lipomatosis of the tongue is reported. The patient was a 72-year-old Japanese male who complained of a bilateral swelling of the tongue. The tongue of the patient was diffusely and markedly enlarged with somewhat nodular appearance in the lateral borders, presenting as a macroglossia. Histopathologically, the biopsy specimen showed adipose tissues which consisted of mature lipocytes. Partial glossectomy was performed. Adipose tissues were interspersed with the muscles fibers and distinct capsule formation was not found. The patient was finally diagnosed as having symmetric lipomatosis of the tongue based on the clinical, radiological and histopathological findings.

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