Linitis plastica-like carcinoma of the urinary bladder.

Two cases of signet-ring cell adenocarcinoma of the urinary bladder with a linitis plastica pattern of infiltration were studied. Mucin histochemistry indicated the presence of neutral and acid mucopolysaccharides and absence of sulphomucin. Immunocytochemistry of the tumour cells was positive for keratin and carcinoembryonic antigen, but negative for prostatic specific antigen and vimentin. The relevance of these observations to the differentiation and histogenesis of these tumours is discussed.