Pulmonary tumor thrombotic microangiopathy: A systematic review of the literature

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.