Subacute right heart failure revealing three simultaneous causes of post-embolic pulmonary hypertension in metastatic dissemination of breast cancer

A 72‐year‐old woman with history of breast cancer only treated surgically was referred to our department for pulmonary hypertension (PH) suspicion. Echocardiogram revealed elevated right ventricular systolic pressure. Computed tomography (CT) angiogram showed no pulmonary embolism (PE), but lung scan revealed two ventilation‐perfusion mismatch areas. Right cardiac catheterization established precapillary PH. Despite treatment with PH specific therapy (sildenafil, ambrisentan, and epoprostenol), her condition worsened rapidly with acute right heart failure (RHF). She died 22 days after admission. Post‐mortem microscopic examination showed a rare combination of PH etiologies consistent with metastasis of breast cancer in pulmonary vasculature including the rare pulmonary tumour thrombotic microangiopathy (PTTM).