Abstract Background Pulmonary tumor thrombotic microangiopathy (PTTM) is a malignancy-associated disease that causes fatal pulmonary hypertension (PH). Due to its rapidly progressive clinical course, antemortem diagnosis is often difficult. PTTM shares several clinical and imaging characteristics with chronic thromboembolic pulmonary hypertension (CTEPH), making differentiation between these two diseases challenging. Case summary A 64-year-old woman with pancreatic cancer treated with chemotherapy presented with shortness of breath and cough over the past 5 months, and was admitted due to 2-week history of worsening dyspnea and peripheral edema. Transthoracic echocardiography found dilated right ventricle, interventricular septal flattening, and severe tricuspid regurgitation. Although contrast-enhanced computed tomography showed no evidence of pulmonary thromboembolism, pulmonary perfusion scintigraphy demonstrated multiple wedge-shaped defects in the peripheral regions of both lungs. Right heart catheterization confirmed pre-capillary PH, and pulmonary angiography revealed vascular narrowing of the peripheral pulmonary arteries. Based on the radiological findings and the relatively slow clinical course, CTEPH was initially suspected. However, pulmonary wedge aspiration cytology—performed by aspirating a blood sample via a Swan-Ganz catheter from the wedged position during right heart catheterization—revealed tumor cells, confirming the diagnosis of PTTM rather than CTEPH. Because of the poor prognosis, the patient received palliative care and died 2 months later. Discussion PTTM is a rare but fatal cause of PH and is rarely diagnosed antemortem. Pulmonary wedge aspiration cytology is a minimally invasive and valuable tool that helps differentiate PTTM from CTEPH and plays a crucial role in guiding both diagnosis and management.
Shimojo et al. (2025) studied this question.