[Malignant carcinoid tumor of the bladder].

One of the first observations of malignant carcinoid of the urinary bladder in a man of 42 is described. Histologically the tumour resembled solid-alveolar transitional cell carcinoma. The carcinoid was verified by finding in the tumour cells electron dense endocrine granules and helix-like rough endoplasmic reticulum. Possible sources of urothelium carcinoid development are discussed.