The spectrum of multiple myeloma: diagnostic and biological implications

Myeloma is a common and well-studied hematopoietic neoplasm with an impressive spectrum of clinical, laboratory, and histological findings. To enhance our understanding of the diversity of myeloma, including its earliest forms, the clinical and pathological findings in 145 cases of myeloma were documented and analyzed. Our analysis indicated that myeloma has at least two distinct subtypes: one presenting with bone lesions and a nodular growth pattern and the other presenting with anemia and an infiltrative growth pattern. The relationship of these two forms to plasma cell biology is not clear, although both types appear to arise in the marrow. The criteria used in this study identified 85% of cases overall, with a range of 70% to 100%, depending on clinical presentation. Immunoperoxidase studies are required to establish the diagnosis in patients with early marrow involvement. Myeloma in younger patients appears to be clinically and pathologically similar to myeloma in older patients. Factors such as dysplasia, immunoglobulin type, or leukemic phase were evenly distributed among clinical presentations and did not apparently identify clinicopathological subtypes of myeloma.