Lymph Node Collision Tumor Consisting of Metastatic Pulmonary Adenocarcinoma and Diffuse Large B-cell Lymphoma

A 67-year-old man presented with a fever and general malaise. Computed tomography showed multiple nodules in the lungs and liver, associated with mediastinal and para-aortic lymphadenopathy. Bone marrow aspiration revealed diffuse large B-cell lymphoma (DLBCL). Renal and liver dysfunction and pancytopenia inhibited chemotherapy administration; the patient subsequently died of multiorgan failure. An autopsy revealed pulmonary adenocarcinoma with metastases to the lungs, liver, and adrenal glands; the DLBCL spread to the liver, spleen, and bone marrow. Adenocarcinoma and DLBCL collision was observed in the mediastinal and para-aortic lymph nodes. This was a rare case of collision metastasis occurring in the lymph node.