A new view of the so-called adenoma malignum of the uterine cervix

Adenoma malignum of the uterine cervix (mucinous type of minimal deviation adenocarcinoma, mucinous MDA), is a unique neoplasm that is difficult to diagnose owing to the deceptively benign appearance of the tumour cells. The present study was undertaken to explore the phenotypic expression of this tumour compared with those of non-neoplastic cervical tissues and of cervical carcinomas of various types. Ten cases of mucinous MDA, 50 cases with non-neoplastic cervical tissues, 13 of cervical adenocarcinoma including the mucinous (endocervical or intestinal type) and endometrioid types, and 2 of mucoepidermoid carcinoma were examined by various histochemical staining methods, including those for gastric mucins, pepsinogen, lysozyme, chromogranin A and carcinoembryonic antigen. The results revealed that mucinous MDA characteristically exhibited gastric phenotypes. The presence of gastric metaplasia was also demonstrated in 9 cases of mucinous MDA and in 5 of the other cases examined. The 7 endocervical-type adenocarcinomas also included 4 that expressed gastric phenotypes, and 2 of the 3 intestinal-type adenocarcinomas showed the same properties focally. These results indicate the presence of a group of lesions expressing gastric phenotypes in the uterine cervix and suggest a close relationship between these lesions. Cervical adenocarcinomas expressing gastric phenotypes are probably derived from MDA.