Carcinosarcoma with a large cell neuroendocrine epithelial component: first report of an unusual biphasic tumour of the urinary bladder.

This article describes the first reported case of carcinosarcoma of the urinary bladder with a large cell neuroendocrine epithelial component. A 61 year old man presented with gross haematuria and underwent resection of a biphasic bladder tumour. The malignant epithelial component showed large cell neuroendocrine differentiation with immunohistochemical reactivity for neurone specific enolase, synaptophysin, and chromogranin. The malignant mesenchymal component did not show specific differentiation by histological or immunohistochemical examination. The differential diagnosis of biphasic tumours in the urinary bladder is discussed, along with a review of the literature.