An ectomesenchymal chondromyxoid tumour on the lateral border of the tongue.

Ectomesenchymal chondromyxoid tumour (ECT) is an extremely rare intraoral mesenchymal tumour. Most of these tumours have been identified on the anterior aspect of the dorsal surface of the tongue. ECT is difficult to diagnose because of its rarity. We report a case of ECT arising on the lateral border of the tongue in a 67-year-old woman. The tumour, measuring 20 × 10 mm in size, was surgically removed. Histopathologically, the tumour was composed of small polygonal cells arranged in sheets, with a myxoid or hyalinized stroma. The tumour boundary was clear; however, the tumour showed a multinodular structure expanding along the tongue surface without obvious capsule. Careful examination revealed the tumour nodule to be spreading in a skip lesion-like fashion away from the main part of the tumour in the striated muscle layer. Although there was no evidence of recurrence at 18 months after the surgery, our observations suggest that surgery for ECT resection with a safety margin is more appropriate than enucleation.

Immunohistological evaluation of Ki-67, p63, CK19 and p53 expression in oral epithelial dysplasias.

BACKGROUND: Oral squamous cell carcinoma develops through a multistep of genetic mutations, and the process can be morphologically recognized as oral epithelial dysplasia. To evaluate the hypothesis that distributional alterations of proliferating and stem cells may be a useful index to estimate the grading and development of epithelial dysplasia, we examined the distribution patterns according to stratified cell layers. METHODS: Sixty-two oral dysplasia cases according to the histological grades were immunohistologically examined and the nuclear expression of Ki-67 and p63 antigens was counted according to epithelial layers as labeling index. RESULTS: The Ki-67 labeling index in the basal and suprabasal layers and that of p63 in the basal layer showed a significant difference between low- and high-grade groups of epithelial dysplasia. CONCLUSION: The architectural alteration of proliferating cell and stem cell distribution in the layers of epithelial dysplasias may provide useful information to evaluate the grading of oral epithelial dysplasias.

Five quantitative trait loci affecting 4-nitroquinoline 1-oxide-induced tongue cancer in the rat.

In our previous study, Dark-Agouti (DA) rats were found to be highly susceptible to 4-nitroquinoline 1-oxide (4NQO)-induced tongue carcinoma (TC), whereas Wistar / Furth (WF) rats were barely susceptible. Interval mapping analysis of reciprocal backcross rats showed two quantitative trait loci (QTL) on rat chromosomes (RNO) 1 and 19. In the present study, a composite interval mapping analysis was applied to 4NQO-induced TC in 130 (DA x WF) F2 rats, demonstrating five independent QTL, Tongue squamous cell carcinoma 1 - 5 (Tscc1 - 5), responsible for phenotypic differences in the size and number of TCs in the two strains. Two of these QTL were mapped on RNO1, and the others were mapped on RNO4, 14, and 19. The DA allele at these loci consistently yielded semidominant susceptibility to TC. Out of the five loci detected in this F2 generation, Tscc1 and 2 were identical to Stc1 and Rtc1 described in our previous study, but the other three were novel. We propose a new nomenclature consistent with their function. Genome-wide screening of the F2 progeny also suggested the presence of three additional QTL on RNO5, 6, and 10. The possible roles of these loci in tongue carcinogenesis are discussed.