Perivascular plasmacytosis: a light-microscopic and immunohistochemical study of 93 bone marrow biopsies

In bone marrow biopsies from 13 hematologically normal persons and from 80 patients with a variety of disorders, we found perivascular plasmacytosis. In all instances except the one case of multiple myeloma, plasma cells were polyclonal and normal in morphology. This was especially pronounced in patients with HIV infection, and in individuals following chemotherapy. In the same patients, sinusoids were also prominent, and appeared dilated. In biopsy sections, small endothelial-lined vessels appeared to arise from attenuation of the sinusoidal lumen. After a short segment of only endothelial-lined vessels, perivascular plasmacytosis appeared. When smooth muscle cells began to line the endothelium, plasma cells virtually disappeared. The biological significance of this finding is unknown. Possibly, the close proximity of plasma cells to endothelial cells early in the development of blood vessels could facilitate entry of immunoglobulins into the blood.