[A case of metastatic urinary bladder tumor from gastric carcinoma--especially mucohistochemical study]

We report a case of metastatic bladder tumor from gastric cancer, which was difficult to differentiate from urachal tumor preoperatively, especially computed tomographic scan, cystoscopy, and biopsy. A 51-year old man visited our hospital with the chief complaint of asymptomatic gross hematuria. He had received subtotal gastrectomy for gastric cancer two years earlier. Because the possibility of urachal tumor could not be excluded, en bloc segmental resection of the bladder, the urachus, and the umbilicus was carried out. This case was diagnosed as adenocarcinoma histologically, but it was difficult to determine whether the case was a metastatic bladder tumor from gastric cancer or urachal tumor by the routine staining method. High iron diamine-alcian blue and paradoxical concanavalin A (ConA) stainings were performed, on the surgical specimens of this case and other urachal tumor already diagnosed. In these cases, metastatic bladder tumor could be differentiated from an urachal one by mucohistochemically paradoxical Con A staining. Seventeen cases of metastatic bladder tumor from gastric cancer including our cases were collected from the Japanese literature and reviewed.