Multiple Myeloma

Abstract

This malignancy has fascinated physicians for more than 100 years because it produces easily identified tumor markers, the M protein and the Bence Jones protein. The plasma cell normally resides in the bone marrow. When it becomes malignant it spreads through the red marrow of bones in a manner similar to the leukemias, crowding out normal marrow elements. Unchecked, this leads to anemia, bleeding, and infection. Death occurs from one or more of these problems. The course of illness in plasma cell myeloma is considerably more complicated than in the leukemias because humoral immunity is compromised by insufficient antibody production by normal plasma cells as the number of these cells decreases. The M protein and the Bence Jones protein damage kidney function. However, the hallmark of the disease is bone destruction, either by the malignant cells or mediated through osteoclasts as shown by Mundy et al. (1974). Finally, hypercalcemia and excess urates may cause further problems in this unusual disease. Very little is known of the factor or factors which may incite myeloma, but radiation and excessive stimulation of immunity seem to be possibilities (Matanoski et al. 1975; Isobe and Osserman 1971). Myeloma is slightly more common in men than in women and is very rare before age 50. Incidence climbs steadily from 4.8 per 100,000 per year at ages 50–54 to 30.8 per 100,000 per year at ages 75–79, declining slightly after that as shown in Fig. 14.1. This is, indeed, a disease of the elderly. Diagnosis is often delayed because bone pain in the elderly suggests osteoporosis or metastatic carcinoma to many physicians before it suggests multiple myeloma.