Urinary bladder metastasis from lung adenocarcinoma: A rare cause of hematuria

We presented an unusual case of hematuria caused by a solitary bladder metastasis from lung adenocarcinoma. A confident diagnosis of secondary adenocarcinoma of the bladder was made by clinical suspicion based on patient's past history, careful examination of tumor morphology, and a directed panel (cytokeratin [CK] 7/CK20/thyroid transcription factor 1) of immunohistochemistry. We sought, through sharing our experience in the investigative and diagnostic process, to contribute to the better understanding of this unusual cause of hematuria.