Carcinoma of the esophagus with adenoid cystic differentiation.

Adenoid cystic carcinoma of the esophagus is a relatively rare lesion which characteristically exhibits a clinically aggressive behavior. In spite of this aggressive nature, it is most often referred to as a counterpart of the more common adenoid cystic carcinoma of salivary gland origin, a comparatively indolent tumor. In this report, the clinical and pathologic findings in a series of six cases of esophageal adenoid cystic carcinomas are contrasted with those of typical salivary gland lesions, and also compared to similar tumors exhibiting "adenoid cystic" differentiation arising in other extrasalivary gland sites. It is concluded that the esophageal tumors, as well as certain similar lesions arising in other extrasalivary gland sites, represent a class of poorly differentiated basaloid neoplasms distinct both clinically and morphologically from the common adenoid cystic carcinoma of salivary gland origin.