Is there hope of improving the prognosis of pulmonary tumour thrombotic microangiopathy?

Pulmonary Tumor Thrombotic Microangiopathy: Case Report and Literature Review

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rapidly progressive pulmonary disease complicated by malignancy. It manifests clinically as respiratory distress with pulmonary hypertension, progressive right sided heart failure, and sudden death. We describe a case of PTTM associated with metastatic gastric carcinoma. This case demonstrates the diagnostic diffi culties in such a rare and rapidly fatal oncological complication. More awareness among clinicians may help make a right diagnosis in the short time available. We also review the literatures to demonstrate the clinical characteristics that might provide clues towards an antemortem diagnosis, and may provide the key in treating PTTM.

[Pulmonary tumor thrombotic microangiopathy]

Pulmonary tumor thrombotic microangiopathy syndrome is a rare clinicopathological entity in which tumor cell micro-emboli in the pulmonary microcirculation induced thrombotic microangiopathy. This can cause respiratory failure, and acute or sub-acute right heart failure. Histological features include micro tumor emboli in the small arteries and arterioles of the lung associated with thrombus formation and fibro-cellular and fibro-muscular intimal proliferation. The diagnosis is however extremely difficult to make before death. Thus, most of the observations reported are based on autopsy data. Very rare diagnostic observations made before death suggest the potential effectiveness of chemotherapy. Many details remain to be elucidated, interdisciplinary research is a priority with close collaboration between pathologists and clinicians to better understand this, often fatal, syndrome. It may be that the use of targeted therapies will improve the very poor prognosis allowing survival of several weeks or months after diagnosis.

A 49-Year-Old Man with Subacute Respiratory Failure and Interstitial Lung Opacities

BACKGROUND Pulmonary arterial hypertension (PAH) results from proliferative vasculopathy involving all layers of the blood vessel. Similar findings may be present in pulmonary hypertension (PH) associated with microscopic tumor embolism, which are thought to be related to the phenomenon of pulmonary tumor thrombotic microangiopathy (PTTM). PTTM is associated with the activation of the coagulation system at the surface of the tumor emboli, resulting in stenosis or occlusion of the vessel. CASE REPORT A 49-year-old man with stage IV gastro-esophageal junction adenocarcinoma presented with complaints of cough and shortness of breath. These symptoms coincided with the initiation of trastuzumab with a new experimental medication with receptor tyrosine kinase blocking activity. A trans-thoracic echocardiogram demonstrated severely increased right ventricle (RV) cavity size with severely decreased RV systolic function. A computed tomography angiography was negative for pulmonary embolism but demonstrated new bilateral pulmonary infiltrates. Bronchoalveolar lavage ruled out an infectious etiology. Trans-bronchial biopsies (TBBx) showed arteriole obliteration by smooth muscle proliferation suggestive of pulmonary vasculopathy. The right heart catheterization (RHC) confirmed severe pulmonary hypertension. Unfortunately, shortly after the RHC, the patient developed pulseless electrical activity cardiac arrest and died. Autopsy results were similar to those of the TBBx, except for diffuse dissemination of tumor cells in the lymphatic channels and small pulmonary vessels, confirming a diagnosis of PTTM. CONCLUSIONS We highlight the limitations of trans-bronchial biopsies in evaluating PTTM. The final diagnosis of PTTM was not made until the autopsy was done.