Urothelial metaplasia of the bladder mucosa. Nephroid-colonic- and signet-ring cell metaplasia.

Three different types of metaplasia of the urinary bladder are described: nephroid metaplasia, colonic metaplasia and signet-ring cell metaplasia. The latter metaplasia was without any histological signs of malignancy and the patient is still alive without recurrence, 12 years after the diagnosis was made. We believe it is the first published case of benign signet-ring cell metaplasia. The patients with nephroid metaplasia were controlled from 3-18 months without recurrence. Two of the patients with colonic metaplasia were followed from 16 to 132 months; both developed recurrences. In patients with metaplasia of the urothelium, follow-up cystoscopy is recommended because of the recurrent nature of the condition and the malignant potential of metaplastic urothelium.