[Immunohistochemical expression of P53 and Ki-67 in diethylnitrosamine-induced carcinomas esophageal: experimental model]. / Expressão imunohistoquímica de P53 e Ki-67 na carcinogênese esofágica induzida pela dietilnitrosamina: modelo experimental.

OBJECTIVE: To evaluate the expression of P53 and Ki-67 during esophageal diethylnitrosamine (DEN)-induced carcinogenesis in 100 mice by immunohistochemistry. METHODS: The animals were assigned to 4 groups, receiving water and food ad libitum. Control groups I and II received weekly esophageal gavage with cold (room temperature) or hot (60-70 degrees C) water, respectively. Experimental groups III and IV were treated with DEN for 3 consecutive days during the week, and one weekly gavage as above. The mice were sacrificed in different periods from day 30 to day 150 after the beginning of the experiment, for collection of esophageal samples which were then submitted to microscopic and immunohistochemical analyses. The temperature of the water administered by gavage was not related to the frequency of esophageal tumors. RESULTS: The expression of Ki-67 was significantly higher in high-grade intraepithelial lesion (I.L.), and the expression of P53 was also higher in low-grade I.L. CONCLUSION: The results emphasize the direct relationship of the carcinogenic process with early cell alterations detected by immunohistochemistry.

Mediastinal teratoma mimicking pleural effusion on chest X-rays.

Teratomas account for 8-13% of all mediastinal tumors. A 27-year-old patient presented with chest pain and dyspnea of prolonged evolution. A chest X-ray revealed near total opacification of the right hemithorax. On a tomography scan of the chest, a collection of heterogeneous fluid, with irregular borders and 10.1 x 11.7 cm in size, was seen in the pleura of the lower two-thirds of the right hemithorax but was not encroaching on any of the adjacent structures. Based on the hypothesis that these findings represented a benign mediastinal teratoma, an exploratory thoracotomy was performed, during which such a teratoma was found and completely excised. The post-operative evolution was favorable. The atypical presentation and considerable growth of the tumor hindered the pre-operative diagnosis.