PULMONARY TUMOR THROMBOTIC MICROANGIOPATHY

Pulmonary tumor thrombotic microangiopathy (PTTM) is characterized by widespread fibrocellular intimal proliferation of the small pulmonary arteries and arterioles In patients with metastatic carcinoma. Microsc opic pulmonary tumor emboli have frequently occurred in patients with malignant tumors; however, few cases of PTTM have been reported. A rar e case of a patient with gastric adenocarcinoma who presented with acu te dyspnea and lethal respiratory failure is described. Histologically , diffuse fibromuscular intimal thickening causing luminal stenosis an d obstruction but containing rather few cancer cells was observed in t he small pulmonary arteries and arterioles. These findings were consis tent with PTTM. Although PTTM is a rare phenomenon, PTTM should be con sidered in the differential diagnosis of acute dyspnea or pulmonary hy pertension in patients with carcinoma.