Carcinogenese esofagica experimental : contribuição ao estudo da histogenese do carcinoma epidermoide

AUTOR(ES)
DATA DE PUBLICAÇÃO

1996

RESUMO

This research was scheduled to study the histogenesis of the epidermoid carcinoma of the esophagus. For so, the Wistar rats and the diethilnitrosamine carcinogen (DEN), in the dosage of 10 mg/kg of weight, were used as an experimental mo deI. The animaIs were kept in separeted cages, helding 5 in each, according to their sexo Aiming to recognise the distinct morfological alterations in the lesions, a chronogram of animal sacrificies was established as follows: TO - control group (ten animaIs) ; T90 (ten animaIs) ; T120 (twenty animaIs) ; T150 (five animaIs) and T200 (twenty animaIs). The control group ingested only water during the experiment, while the others ingested DEN solution, and were sacrificed in those determined intervals. The macroscopic study and the lugol staining for temporary observation were performed, and its classification obeyed the Japanese School. Among the animals that survived in groups T120, T150 and T200, 183 esophageal carcinomas were found, with an average of 6.1 % focus of carcinomas per esophagus examined. The macroscopic lesions diagnosed were: type Ip - eleven carcinomas (6.01%) ; type Ipl - eight carcinomas (4.37%) : type lIa - thirty three carcinomas (18.05%) ; type IIb - one hundred and two carçtnomas (55.73%) ; type 11 - five carcinomas (2.73%) ; mixed type - nine carcinomas (4.92%) ; Bomnann I - three carcinomas (1.64%) ; Bomnann 11 - five carcinomas (2.73%) and Bomnann 111 - seven carcinomas (3.82%). The microscopic classification of these } 8H carcinomas also followed the Japanese School parameters. It was diagnosed 119 carcinomas In situ, limited to the mucosa (65.02%), and 24 microinvading carcinomas which did invade the muscularis mucosa (13.11%). Among the latest, seven were mm1 (3.82%), fiften mm2 (8.19%), and two mm3 (1.09%). The submucous carcinomas presented different levels of submucosa invasion. Twenty five carcinomas were diagnosed (13.66%), from which 12 were sml (16.55%), ten sm2 (5,46%), and three sm3 (1.63%). Fiften (8.19%) invading carcinomas did occur. The statistical X2 test showed a sig llificant difference (p <0.05) between the levels of carcinoma invasion of groups T120 and T150 versus T200, with the latest showing a greater number of invading lesions. It was observed that the elevated lesions of type Ip and Ipl presented levels of Invasion mainly of submucosa (11/18 = 61.11% of the cases). In contrast, the Tia superficiallesions presented levels of invasion limited mainly to the mucosa in 70.8% of the cases (17/24), while the type IIb superficiallesions were alllimited to the epithelium, representing 85.7% (119/162) of the In situ carcinomas. The results of this study are in accordance with the consulted literature. While the elevated lesion tends to be more invasive, the type IIb and IIa flat lesions are limited mainly to the epithelium and the mucosa. One of the objectives of this study was to obtain the possible histological differentiation between dysplasia and In situ carcinoma (intraepithelial). The histological analysis did not show any case of dysplasia. and the alterations of celular maturation in the epithelial lesion were similar to the microinvading carcinomas, submucous and invading, so they were classified as ln situ carcInomas. It is important to consider that, probably, at the very beginning of the celular multipliction there is already a tumoral genotype which reaches a phenotypical expression of carcinoma that can be recognised at once. The main difficult in terminology consists in using two expressions (dysplasia and In situ carcinoma) to nominate the same biological processo The most significant problem that arises is that, depending on the terminology employed, distinct therapeutic conducts may be dictated to the same illness, with evident detriment to the patient

ASSUNTO(S)

cancer - tratamento esofago - histologia carcinogenese

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