Pulmonary tumor thrombotic microangiopathy: A systematic review of the literature

Abstract

BACKGROUND Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare complication of cancer that was described almost 30 years ago. However, a minimal amount is known about this condition making pre-mortem diagnosis and treatment difficult. OBJECTIVES We aimed to systematically review and summarize the epidemiology, clinical manifestations, radiologic and hemodynamics features, diagnostic procedures and outcomes of PTTM. METHODS MEDLINE was searched (January 1990–November 2019) for case reports on PTTM. RESULTS A total of 132 studies were included (217 cases), including 126 case reports and 6 autopsy series. Gastric cancer (53%) and adenocarcinoma (87%) were the most common site of cancer and histological subtype, respectively. Mean age at presentation was 56 ± 16 years old. Most patients reported dyspnea, although symptoms were variable and nonspecific. Pulmonary hypertension was frequently documented either by transthoracic echocardiogram (97/103) or right heart catheterization (39/39). The diagnosis was made antemortem in only 29 patients using open lung biopsy (n = 12), transbronchial biopsy (n = 14) and CT-guided needle biopsy (n = 1), pulmonary microvascular cytology (n = 6); whereas, clinical presentation was suggestive of PTTM in 2 patients. Anticoagulation (n = 39), pulmonary hypertension-targeted treatments (n = 27), chemotherapy (n = 21), imatinib (n = 6) and thrombolysis (n = 5) were used as treatment strategies. Prognosis was poor with most patients dying within days or weeks of their admission. CONCLUSIONS PTTM is a rare syndrome that manifests as progressive dyspnea, pulmonary hypertension and right heart failure. PTTM is associated with a poor prognosis. Transbronchial biopsy and pulmonary microvascular cytology may represent alternatives to open lung biopsy to achieve an antemortem diagnosis of PTTM, although the best treatment strategy remains elusive.