Final answer:
Plasmacytes can appear in the peripheral blood in diseases like multiple myeloma and Waldenstrom macroglobulinemia.
Step-by-step explanation:
Plasmacytes are a type of white blood cell that are derived from B lymphocytes. They are typically found in the bone marrow and lymphoid tissues, but can also appear in the peripheral blood in certain diseases.
One example of a disease in which plasmacytes appear in the peripheral blood is multiple myeloma, a type of blood cancer. In multiple myeloma, abnormal plasmacytes multiply uncontrollably and crowd out healthy blood cells.
Another disease in which plasmacytes can be found in the peripheral blood is Waldenstrom macroglobulinemia, a rare type of non-Hodgkin lymphoma. In this disease, abnormal plasmacytes produce excessive amounts of a type of antibody called IgM.