[Diffuse large B-cell lymphoma with intravascular involvement of neoplastic CD5-positive cells].

A 77-year-old man was admitted because of fever. A small number of large CD20-positive neoplastic cells were seen in the bone marrow specimen. Clinical symptoms improved with oral prednisolone. After 11 months, abdominal CT scan revealed a liver mass. The biopsy specimen from the liver mass showed diffuse infiltration of large CD20-positive neoplastic cells. The patient was diagnosed as having diffuse large B-cell lymphoma. It was of particular interest that only neoplastic B cells within small blood vessels in the liver mass were positive for CD5. The patient died of lymphoma three months after diagnosis.