[Clinicopathologic and immunohistochemical study of 23 cases of mesenchymal chondrosarcoma].

OBJECTIVE: To study the clinicopathologic and immunohistochemical features of mesenchymal chondrosarcoma. METHODS: The clinical and histologic features of 23 cases of mesenchymal chondrosarcoma were analyzed. Immunohistochemical study was also performed in 14 of the cases. RESULTS: The age of patients ranged from 12 to 47 years. Fourteen of them occurred in males. Thirteen cases involved the bony skeleton and 5 cases affected the soft tissue. The patients presented with pain and/or swelling. Histologically, the tumor consisted of a mixture of undifferentiated small round cells and hyaline cartilage. Transition between the two components was demonstrated and growth plate-like cartilage was observed. Immunohistochemical study showed that the small round cells were positive for Sox9 (14/14), CD99 (12/14), vimentin (6/14), CD56 (4/14), CD57 (4/14), neuron-specific enolase (3/14) and desmin(1/14). They were negative for Coll-II, S-100 protein, epithelial membrane antigen, pan-cytokeratin, synaptophysin, chromogranin A, CD34 and c-erbB2. CONCLUSIONS: Mesenchymal chondrosarcoma is a rare malignant tumor. Thorough histologic examination, when coupled with immunohistochemical findings, is helpful in arriving at a correct diagnosis.

[Yolk sac tumor of mouth floor].

Yolk sac tumor (endodermal sinus tumor) is a malignant germ cell tumor which usually arise in gonads. It is rare occurring in the oral cavity. Here, a yolk sac tumor of mouth floor was reported and relevant literatures were reviewed.

Case report of rapidly progressive proliferative verrucous leukoplakia and a proposal for aetiology in mainland China.

Proliferative verrucous leukoplakia (PVL) is a rare oral leukoplakia and has four features such as chronic proliferation, multiple occurrences, refractoriness to treatment and high rate of malignant transformation. As mentioned above, most PVL cases processed to malignancy over many years, sometimes 20 years. However, this report described a case of rapid progress, which had malignant transformation in a short period. Additionally, the aetiology of PVL was discussed and immunity was proposed as the possible cause.

[Role of ataxia telangiectasis mutated in the oncogenesis of oral squamous cell carcinoma].

OBJECTIVE: To investigate the role of ataxia telangiectasis mutated (ATM) gene in the oncogenesis and progression of oral squamous cell carcinoma (OSCC). METHODS: A total of 61 formalin-fixed and paraffin-embedded samples were obtained from patients with hyperkeratosis, oral leukoplakia, OSCC and normal healthy controls. The expression of ATM protein in all of the samples was investigated by streptavidin-peroxidase immunohistochemistry assay. PCR was also performed to detect the loss of heterozygosity (LOH) in D11s2179 of ATM gene. The correlations between ATM and the clinical and histopathological characteristics were also investigated. RESULTS: The results indicated that the ATM expression was increased in oral premalignant lesions (P<0.05). For OSCC, 68.8% samples showed normal or increased ATM expression, while 31.3% had decreased or absent ATM expression. Significant differences were found between the group of decreased or absent ATM expression and that of normal or increased expression over the histopathological grade and lymph node metastasis state. PCR results displayed that none of the samples from oral premalignant lesions showed abnormal changes, while 3 of the OSCC (9.38%) showed loss of heterozygosity (LOH) and 2 (6.25%) with microsatellite instability (MSI). Those 3 samples of LOH showed absent ATM expression. CONCLUSION: These findings indicated that the over expression of ATM may contribute to prevent carcinogenesis of OSCC. ATM inactivation may be one of the genetic alterations of the molecular progression of OSCC.

[Metastasizing pleomorphic adenoma of the submandibular gland: a case report].

Metastasizing pleomorphic adenomas without histological evidence of malignancy have rarely been reported. A case of 30-year-old woman with a mass which showed a benign pleomorphic adenoma appearanced histologically in the left submandibular gland and right supercollarbone respectively was described. Eight years ago, the patient suffered from pleomorphic adenoma of the left submandibular gland. It revealed histopathologic features consistent with the recurrent and metastasizing tumor. The clinic pathological features, possible mechanism and prevention approach of metastasizing pleomorphic adenoma were discussed based on previously reports in the literature.

[A case report on canceration of proliferative verrucous leukoplakia].

Proliferative verrucous leukoplakia (PVL) is a particular form of oral leukoplakia clinically characterized by chronic proliferation, multiple occurrence, and intractability. It is seen mostly among elderly women and often involves bucca, palate, gingiva and tongue. Its canceration rate is very high. This article reports a case of a middle-aged woman with progressive PVL which became focally malignant who complained about buccal and palatal exophytic white patches, and discusses the possible pathogenic mechanism, diagnosis, treatment, prognosis of PVL and differentiation between PVL and other types of oral leukoplakia by way of reviewing relevant literature.

Nucleotide sequences and functions of the Epstein-Barr virus latent membrane protein 1 genes isolated from salivary gland lymphoepithelial carcinomas.

Epstein-Barr virus (EBV) infection is associated with salivary gland lymphoepithelial carcinoma (SLEC) and nasopharyngeal carcinoma (NPC). EBV is a ubiquitous herpes virus world wide, but EBV-associated SLEC and NPC are prevalent in restricted regions such as south areas of China, Southeastern Asia and Greenland (Eskimos). To examine whether particular EBV variants play roles in the development of SLEC and NPC, we isolated the complete EBV LMP1 genes from 12 paraffin-embedded biopsy samples of SLECs isolated from China, Taiwan and Russia, and compared these LMP1 genes with those of NPC (CAO) and the prototype B95-8 EBV. Nucleotide sequence analysis showed that SLECs LMP1 is more similar to that of CAO than that of prototype B95-8. The analysis also identified several conserved (67-100%) variations in SLEC-LMP1 and CAO-LMP1 distinct from B95-8-LMP1. These included 10-amino acid deletion, 5-amino acid deletion and 12-single amino acid variations. A SLEC-LMP1 gene with the aforementioned conserved variations inhibited the growth of an embryonic kidney cell line (293T), highly activated the NF-kappaB pathway, and these activities were equivalent to those of B95-8 and CAO. These findings suggest that the biological functions of SLEC-LMP 1 are similar to those of B95-8-LMP1 and CAO-LMP1, and that these amino acid variations including the well-known 10-aa deletion did not affect these two prominent activities. While the present results could not uncover functional differences between SLEC-LMP1 and B95-8-LMP1, the nucleotide sequences and the molecular clone of LMP1 directly isolated from SLEC patients will be a useful tool to identify the high-pathogenic EBV strain(s), associated with SLEC and NPC.

[Epstein-Barr virus infection in benign lymphoepithelial lesions with malignant transformation of salivary glands].

OBJECTIVE: To examine the role of Epstein-Barr virus (EBV) infection in benign lymphoepithelial lesions with malignant transformation of salivary glands. METHODS: 2 cases benign lymphoepithelial lesions with focal malignant transformation (BLEL-FMT), 14 cases of malignant lymphoepithelial lesion (MLEL) and 4 cases of benign lymphoepithelial lesion (BLEL) of salivary glands, 4 cases of nonspecific chronic sialadenitis were examined. Sections were cut from the paraffin blocks and performed in situ hybridization (ISH) for EBV encoded small RNA-1 (EBER-1) using 30-base synthesized oligonucleotide probe and polymerase chain reaction (PCR) for BamHI-W regein of EBV DNA (123 bp). RESULTS: In ISH, strong signals for EBER-1 were obtained in most of epithelial cell nuclei in examined specimens of BLEL-FMT, no matter in benign or malignant areas and in all specimens of MLEL (14/14), PCR demonstrated a DNA fragment of 123 kbp in 2 cases of BLEL-FMT and 12 cases of MLEL (12/14). In contrast, there were no significant ISH/PCR signals in examined BLEL and nonspecific chronic sialadenitis. CONCLUSIONS: A few cases of MLEL may arise from BLEL and EBV may plays an important role in the pathogenesis of BLEL-FMT of salivary glands.

[Epstein-Barr virus infection in lymphoepithelial carcinoma of salivary glands in Sichuan Chinese].

OBJECTIVE: To determine the prevalence of Epstein-Barr virus (EBV) infection in lymphoepithelial carcinoma (LEC) of salivary glands in Sichuan Chinese and discuss the role of EBV infection in pathogenesis of LEC. METHODS: Paraffin sections of 16 cases of LEC and 4 cases of benign lymphoepithelial lesion (BLEL) of salivary glands, 4 cases of non-specific chronic sialadenitis were examined by in situ hybridization for EBV encoded small RNA-1 (EBER-1) using 30-base synthesized oligonucleotide probe. RESULTS: Strong signals for EBER-1 were obtained in most of tumor cell nuclei in all the specimens of LEC (16/16); in contrast, there were no significant signals observed in the examination of 4 cases of BLEL and 4 cases of non-specific chronic sialadenitis. CONCLUSION: The results indicate that EBV plays an important role in the pathogenesis of LEC of salivary glands in Sichuan Chinese.