Pulmonary tumor thrombotic microangiopathy (PTTM) is a fatal, malignancy-related respiratory complication; we herein report a PTTM case induced by metastatic prostate cancer. An 81-year-old Japanese man developed dyspnea. High-resolution computed tomography (HRCT) revealed ground-glass opacities spread across bilateral lung fields. Pulmonary microvascular aspiration cytology detected prostate cancer cells. As PTTM was highly suspected, docetaxel chemotherapy was performed immediately. His respiratory condition and HRCT findings improved temporarily, but he died approx. 6 weeks after admission. Autopsy showed fibrocellular intimal proliferation of small pulmonary arterioles, which confirmed the diagnosis of PTTM induced by prostate cancer. As in the present case, it is often difficult to confirm the presence of not only tumor embolization but also fibrocellular intimal proliferation before the patient’s death.