A Rare Case of Pulmonary Tumor Thrombotic Microangiopathy Associated with Micropapillary Urothelial Carcinoma of the Urinary Bladder: An Autopsy Case.

A 70-year-old woman was hospitalized with dyspnea. A transthoracic echocardiogram indicated an elevated systolic pulmonary artery pressure, and the cytology specimens obtained using a pulmonary artery catheter confirmed adenocarcinoma metastasis. Diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) detected high-signal-intensity lesions in the urinary bladder. The patient died of respiratory failure and a postmortem examination was performed. Tumor cells in the bladder were immunohistochemically positive for GATA3, indicating micropapillary urothelial carcinoma, which is a rare variant of urothelial carcinoma and considered an adenocarcinoma subtype. This case is the first autopsy case of pulmonary tumor thrombotic microangiopathy (PTTM) associated with micropapillary urothelial carcinoma of the urinary bladder.