In the trephine biopsy the neoplastic plasma cells show an interstitial or diffuse pattern of infiltration. Normal plasma cells are perivascular in distribution Plasma cell morphology is usually abnormal with increased cell size, prominent nucleoli, vacuolated cytoplasm and multi-nucleated cells. Myeloma plasma cells in bone marrow. Myeloma BM trephine biopsy. Myeloma plasma cells are phenotypically abnormal and can be distinguished from normal on the basis of their reduced expression of CD19 and CD45 and increased expression of CD56 and CD138.
Karyotypes are commonly complex.
A number of chromosomal translocations into the IgH locus at 14q32 have been identified recently. Poor prognostic groups are identified by high beta 2 -microglobulin or high number of circulating plasma cells at presentation. The outcome is affected by major complications including the development of renal disease and amyloidosis The aim of conventional therapy is to induce a period of plateau in which the patient is asymptomatic and the paraprotein and beta 2 m levels are stable. High dose chemotherapy with stem cell support in younger patients may induce a complete remission and improved overall outcome has been reported. These results await confirmation.