A Case of Pulmonary Tumor Thrombotic Microangiopathy (PTTM) Caused by Gastric Cancer

Abstract

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare and fatal cancer-related complication that is clinically difficult to diagnose. PTTM is pathologically characterized by pulmonary vascular tumor emboli and intimal proliferation leading to pulmonary artery stenosis or obstruction. A 62-year-old man was admitted to the hospital because of worsening exertional dyspnea. We clinically diagnosed this as pulmonary thrombotic embolism (PTE) because of the high serum D-dimer level and right ventricular load, as demonstrated by cardiac ultrasound, despite the fact that enhanced chest CT did not show any pulmonary thrombosis. Despite treatment for PTE, he died of acute respiratory failure the day after admission. Autopsy revealed that he had gastric cancer (signet-ring cell carcinoma) and pulmonary vascular and lymphatic tumor emboli with organized thrombosis and vascular intimal proliferation consistent with PTTM. PTTM should be considered in the differential diagnosis of progressive acute respiratory failure of unknown origin.