Pulmonary tumor thrombotic microangiopathy (PTTM) is histopathologically characterized by proliferation of intimal myofibroblasts in the small pulmonary arterioles, induced by tumor microemboli. Patients develop rapidly progressive and severe cardiopulmonary failure, and the clinical course of this disease is fatal. Conventional radiologic findings are often minimal or nonspecific, making diagnosis difficult before death. We report 2-(F-18)-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) images of PTTM, which illustrate the characteristic findings of this clinical entity. FDG-PET can be helpful for the diagnosis of PTTM.