[Subacute cor pulmonale due to microscopic pulmonary tumor embolism]

We report a case of subacute pulmonary hypertension caused by microscopic pulmonary tumor embolism due to the dissemination of gastric cancer cells. The patient, a 61-year-old man with no history of malignant diseases, was admitted to our hospital on October 14 in 1998 because of cough and dyspnea on effort, that had developed since the previous month. On admission, chest radiography including CT scans showed slight cardiomegaly and disseminated reticulonodular shadows predominating in the lower lung fields of both lungs, and arterial blood gas analysis disclosed severe hypoxemia. Lung perfusion scintigraphy revealed multiple irregular defects in both lungs. Echocardiography indicated right ventricular overload, and the pulmonary artery systolic pressure was estimated to be higher than 80 mmHg. Disseminated intravascular coagulation (DIC) developed on the 6th day of hospitalization. Multiple pulmonary embolism with DIC of unknown cause was diagnosed, and the patient was given anticoagulant therapy with heparin. However, he died of respiratory failure on the 7th day of hospitalization. At autopsy, an invasive cancer was found in the stomach, resembling type IIc early gastric cancer. The lumens of the pulmonary arterioles were significantly narrowed by fibrocellular proliferation and thrombi accompanying tumor cell clusters, and some of the microvessels were completely occluded. Disseminated microscopic pulmonary metastasis of malignant tumors should be included in the differential diagnosis of subacute pulmonary hypertension due to multiple pulmonary embolism of unknown cause.