Antemortem Diagnosis of Pulmonary Tumor Thrombotic Microangiopathy in a Patient with Recurrent Breast Cancer: An Autopsy Case Report.

Herein, we report a case of a patient with recurrent breast cancer who was diagnosed antemortem with pulmonary tumor thrombotic microangiopathy (PTTM) using wedge aspiration cytology of the pulmonary artery after breast cancer surgery.The patient was a 50-year-old woman who underwent mastectomy and axillary lymph node dissection for stage IIIA (T3N2M0) triple-negative left breast cancer. Postoperative follow-up was performed with radiotherapy and anticancer chemotherapy. Seventeen months after the surgery, the patient was hospitalized for right heart failure and diagnosed with pulmonary arterial hypertension. The patient was diagnosed with PTTM following the detection of malignant cells in the pulmonary artery using wedge aspiration cytology. Anti-pulmonary hypertension therapy was administered; however, the patient did not respond and died 26 days after admission. Autopsy revealed multiple microscopic tumor emboli in the pulmonary artery. In portions of the pulmonary artery without embolization, fibro-cellular intimal hyperplasia and stenosis were observed. Tumor embolism was expressed for CK7+/CK20-, consistent with the primary breast cancer.Since the primary pathophysiology of PTTM entails narrowing due to fibro-cellular intimal hyperplasia rather than multiple tumor thrombi, the efficacy of chemotherapy combined with vasodilators is discussed.