[Small cell undifferentiated carcinoma of the urinary bladder: report of a case].

: Small cell carcinoma of the urinary bladder is an uncommon tumor. We report a case in a 80 year-old man. The patient had gross hematuria. Urographic and echographic studies revealed a sold tumor on the right wall of bladder. Pathologic study revealed a deeply invasive tumor composed of small, uniform, round and spindled shaped cells with hyperchromatic nuclei and numerous mitosis. The immunohistochemical reaction was positive for Neuron Especific Enolase and Keratin. No metastasis were found at clinical stating (T2 No Mo). We discuss the differencial diagnosis, prognosis and histogenesis of this tumor.