We pathologically investigated the effects of water irrigation during Er:YAG laser irradiation on wound healing in mouse skin. Fifty-one 6-week-old ICR male mice were used in the present study. Dermal wounds were generated on the skin of the backs using the Er:YAG laser at 100 mJ/pulse and 10 Hz with (4 ml/min) or without (control) water irrigation. Mice were then sacrificed on 0, 1, and 3 days after laser irradiation, and the crust of the skin and thickness of the thermal coagulation layer were evaluated pathologically. The epidermis extended faster in the water irrigation group than in the control group on 1 day. The epidermis with keratinized layers became thicker and the crust had completely detached after 3 days in the water irrigation group. The thermal coagulation layer was thinner in the water irrigation group than in the control group. Apoptotic cell death was prominent in the control group. Detachment of the crust was observed after 3 days in 50% of the water irrigation group and 20% of the control group. These results demonstrated that Er:YAG laser irradiation with water irrigation promoted faster wound healing

Carcinoma ex pleomorphic adenoma is a rare malignant salivary gland tumor. The carcinomatous component of the carcinoma ex pleomorphic adenoma is mostly one type such as adenocarcinoma NOS, salivary duct carcinoma and undifferentiated carcinoma. We present a case of carcinoma ex pleomorphic adenoma including two carcinomatous components. The tumor occurred in the palate of a 70-year-old man. Histopathologically, the tumor was composed of both benign pleomorphic adenoma and the carcinoma area that showed adenocarcinoma NOS and squamous cell carcinoma. Finally this case was diagnosed as carcinoma ex pleomorphic adenoma including two carcinomatous components

A rare case of primary intraosseous squamous cell carcinoma(PISCC) arising from lining epithelium of a dentigerous cyst is described. The case occurred at the left mandibular 3rd molar region in a 56-year-old Japanese woman. Clinical observation revealed cyst formation with an impacted 3rd molar, a common finding in dentigerous cyst, in the left mandible. Histopathologically, the lining epithelium of the cyst demonstrated transition from epithelial dysplasia to invasive squamous cell carcinoma(SCC). This case was diagnosed as PISCC arising from lining epithelium of a dentigerous cyst.

This report describes a case of odontogenic cyst with keratinization and dysplastic change of lining epithelium, which showed the manifestation of inflammatory radicular cyst, clinically. A 28-year-old man complained of dull pain in the right mandibular molar region. Radiographically a well-defined oval cystic lesion with non-vital teeth, a common finding in radicular cyst, was observed. Microscopically, the lining epithelium of the cyst demonstrated both keratinization and severe epithelial dysplasia. Atypical findings such as hyperchromatic nuclei, increase of N/C ratio and drop shaped rege ridge were observed in the lining epithelium. However, definite invasion into fibrous connective tissue was not found. Immunohistochemically, the dysplastic lining epithelium was highly positive for proliferative marker, Ki-67. Based on the dysplastic changes of lining epithelium, this periapical lesion would be considered to be signs of malignant change. From this case, we conclude that definitive diagnosis by microscopical examination should be made, even if the periapical lesion would be clinically considered as inflammatory radicular cyst.