Pulmonary metastasis with coexisting pulmonary mucosa‐associated lymphoid tissue (MALT) lymphoma 20 years after endometrioid adenocarcinoma surgery: A case report

Late pulmonary metastasis from endometrioid adenocarcinoma (EA) is rare, and occurrence after >20 years is extremely rare. Here, we report a case of pulmonary metastasis with coexisting pulmonary mucosa‐associated lymphoid tissue (MALT) lymphoma that occurred 20 years after surgery for EA. A 60‐year‐old Japanese woman had previously undergone surgery for primary EA, and 20 years later presented with an abnormality that was detected on chest radiography. Chest computed tomography (CT) revealed two nodules in the right lower lung lobe, which were suspected to be primary lung cancer. Wedge resection was performed, and the intraoperative pathological diagnosis was that of adenocarcinoma with MALT lymphoma; this prompted additional right lower lobectomy. The final pathological diagnosis was pulmonary metastasis from EA with coexisting MALT lymphoma. This is probably the first report on late pulmonary metastasis coexisting with MALT lymphoma 20 years after surgery for EA. Surgeons should be aware of the possibility of late pulmonary recurrence of EA after more than 20 years and should consider aggressive resection. KEY POINTS: SIGNIFICANT FINDINGS OF THE STUDY: Although extremely rare, pulmonary metastasis can occur more than 20 years after surgery for endometrioid adenocarcinoma. Furthermore, pulmonary metastasis from endometrioid adenocarcinoma may coexist with mucosa‐associated lymphoid tissue lymphoma. WHAT THIS STUDY ADDS: Endometrioid adenocarcinoma requires long‐term postoperative follow‐up to detect recurrence, even in early‐stage cases. Video‐assisted thoracoscopic surgery (VATS) is useful for resecting pulmonary metastasis from endometrioid adenocarcinoma.