An autopsy case of pulmonary tumor thrombotic microangiopathy that developed during chemotherapy for salivary duct carcinoma of the parotid gland

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rapidly progressive cancer-related disease with a dismal clinical course. The patient in this report was a 43-year-old man with metastatic salivary duct carcinoma arising from the parotid gland. Combined androgen blockade therapy was administered started as first-line treatment, but failed after 5 months, followed by docetaxel plus carboplatin therapy as second-line treatment, which failed after 3 months. Genomic profiling revealed a BRAF V600E mutation, and combined BRAF and MEK inhibitor therapy was started as third-line treatment. The cancer remained stable during the first 10 months of third-line treatment, but treatment was subsequently discontinued due to the onset of symptoms of fatigue, myalgia and arthritis. Twenty days after the onset of these symptoms and interruption of third-line treatment, the patient was urgently admitted to hospital with respiratory distress and severe thrombocytopenia. CT images at the time of admission led our radiologist to the possibility of PTTM, but the patient died the day after admission and autopsy findings indicated that PTTM was the cause of death. This report describes a very informative case of PTTM with sequential imaging and detailed autopsy findings were available and provides a literature review.