Argentaffin cell adenocarcinoma of the stomach: An atypical carcinoid?

A unique morphological entity of a gastric tumor composed predominantly of argentaffin cells characteristically forming tubular structures is reported. The patient was a 39-year-old man and presented no clinical manifestations suggestive of an argentaffinoma. The gastric lesion was removed as a usual gastric carcinoma of the Borrmann II type, and routine histologic findings were interpreted as a well-differentiated adenocarcinoma of the mucus-secreting type until the most component cells of this tumor were found to be argentaffin cells accompanied by fewer mucus-secreting cells. A subsequent diagnosis of argentaffin cell adenocarcinoma of the stomach was tentatively made. For an explanation of the pathogenesis of this particular tumor, one possibility may be that the neoplastic cells of both argentaffin and mucus-secreting varieties may have originated from the more primitive cells capable of differentiating themselves into either variety. It is further suggested that this peculiar tumor should be classified as an argentaffinoma or a carcinoid of an extreme atypicality.