A Case of Recurrent Pulmonary Tumor Thrombotic Microangiopathy Associated With Gastric Adenocarcinoma Following Imatinib Discontinuation

Pulmonary tumor thrombotic microangiopathy (PTTM) is a severe and fatal disease that rapidly causes pulmonary hypertension (PH). While imatinib shows potential for treating PH related to PTTM, it remains unclear if imatinib should continue or be discontinued after improvement in PH. Here, we present a case with PTTM in which PH was controlled for 9 months on imatinib, but recurred immediately after discontinuing of imatinib. The patient experienced worsening dyspnea for over 3 weeks and was diagnosed with PTTM associated with gastric adenocarcinoma. She was treated with imatinib and pulmonary vasodilators, which improved her PH, and she was discharged 1 month after starting chemotherapy. Eight months after the initial hospitalization, tumor progression was observed and second‐line chemotherapy was initiated, leading to pancytopenia and imatinib discontinuation. The patient was rehospitalized for worsening PH 3 weeks after imatinib discontinuation, with recurrent PTTM being considered as a possible underlying cause. Although the PH improved with the reintroduction of imatinib and pulmonary vasodilators, we could not control the tumor progression, and she died of respiratory failure due to PTTM and lymphangitic carcinomatosis 1 month after the second hospitalization. Imatinib continuation is important for patients with PTTM with tumor progression, even after PH improvement.