Signet-ring cell adenocarcinoma of rectum: a histological, histochemical and electron microscopic study

Abstract

A signet-ring cell adenocarcinoma of rectum removed from a 71-yr-old woman was examined by light microscopy and EM. Most of the mucin in the signet-ring cells was of the neutral type, although acidic, mostly non-sulfated mucin was also present. Three other types of neoplastic cells were seen: undifferentiated cells, cells with intracytoplasmic lumina and argentaffin cells. The similarities between this tumor and tumors described in the stomach, appendix and breast are discussed.