[A case of signet ring cell carcinoma of the urinary bladder]

A rare vesical carcinoma, arising in a 47-year-old male, is described. The tumor developed from the left ureteral orifice and posterior urethra, showing a nonpapillary appearance with a wide stalk. By light microscopy, the carcinoma was found to be mainly composed of signet ring cells and associated with small foci of transitional cell carcinoma. The previously reported cases of signet ring cell carcinoma of the urinary bladder were reviewed with a special reference to the manifold potentiality of the urothelium.