Primary signet-ring cell carcinoma of the urinary bladder. Report of two cases with histochemical studies.

Two cases of primary signet-ring cell carcinoma of the urinary bladder are presented with histochemical studies. The signet-ring cell carcinoma of the bladder is a rare variant of mucus-producing vesical adenocarcinoma: sixteen cases have been reported in the Occidental and two other cases in Japanese literature. Most of the cases were discovered in the advanced stage and the prognosis was poor: necessity of early detection by cytological examination and treatment with surgery is stressed. The histochemical evidence for the similarity of the neoplasm to colonic epithelium in mucus production is illustrated and the grade of malignancy is discussed from the view of mucus production by the neoplasms.