Pulmonary tumor thrombotic microangiopathy caused by an ovarian cancer expressing tissue factor and vascular endothelial growth factor

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare clinicopathologic entity causing severe pulmonary hypertension, right-side heart failure, and sudden death. Its histologic features include widespread tumor emboli of the small arteries and arterioles of the lung, associated with thrombus formation and fibrocellular and fibromuscular intimal proliferation. The most frequent causative neoplasm for PTTM is gastric cancer, but lesions in other organs, including the ovary, have been occasionally identified as primary causes. Detailed molecular mechanisms underlying PTTM remain unclear, but some studies have suggested that tissue factor (TF) and vascular endothelial growth factor (VEGF) expressed by tumor cells may be involved in the pathogenesis for cases of gastric cancer. However, little is known about these molecules in PTTM caused by neoplasms of non-gastric origin.Here, we report the autopsy findings of a 42-year-old woman with ovarian cancer showing positive immunoreactivity for both TF and VEGF who died suddenly of PTTM. The present case provides support for the conclusion that these factors may be involved in the pathogenesis of PTTM, independent of the causal neoplasm.