LAUSR

Although intravascular large B‐cell lymphoma (IVLBCL) is an extranodal lymphoma characterized by the selective growth of lymphoma cells within the lumina of small vessels, we here report three autopsy cases of IVLBCL characterized by the proliferation within large blood vessels. These three cases were diagnosed as IVLBCL of the bone marrow or skin biopsy. Two cases died suddenly before treatment, whereas the other died during treatment. Autopsies showed a large embolus of dense lymphoma cells extending from the truncus pulmonalis to the pulmonary arteries in Case 1, emboli of lymphoma cells in the aorta and carotis in Case 2, and a mass of lymphoma cells blocking the lumen of the aortic arch in Case 3. This is the first report of IVLBCL involving large blood vessels, and it is essential to note that this type of IVLBCL might cause sudden death because of tumor emboli within large blood vessels.