Adenoid cystic carcinoma of the uterine cervix: ultrastructure, immunofluorescence, and criteria for diagnosis.

An example of adenoid cystic carcinoma of the cervix was recently encountered in our laboratory and studied by histochemistry, electron microscopy, and immunofluorescence in order to compare the neoplasm with adenoid cystic tumors at other sites and to establish criteria for diagnosis. Histochemically, cervical adenoid cystic carcinoma showed the two types of mucin, epithelial and stromal, as expected in adenoid cystic carcinomas of other organs. Ultrastructurally, this tumor was characterized by redundant basal lamina forming pseudocysts, intercellular spaces, and occasional true lumens with microvilli. Immunofluorescence studies showed that the cells contain at least two antigenically different types of filaments, actin and keratin, and that the cells produce true basement membrane (collagen IV). The presence of actin suggests myoepithelial differentiation even though the tumor probably originated from the cervical reserve cells, and myoepithelium is not a known component of normal cervix. This study shows that cervical adenoid cystic carcinoma is a distinct entity which can be identified and separated from other types of cervical adenocarcinomas.