Distinctive diagnostic features of material aspirated from marrow in metabolic bone diseases

In a series of cases of Paget's disease of the bone, two types of cells not previously described were observed in material aspirated from bone marrow in areas of osteitis deformans. One type was mononuclear, the other was giant, multinucleated and syncytial. They have been identified as osteoblasts and osteoclasts, respectively. The identification was based mainly on correlation with the histologic picture of osteitis deformans and of normal-growing bones as seen in section studies. Both osteoblasts and osteoclasts were recovered in aspirated bone marrow material in other instances of metabolic bone diseases associated with increased bone repair and bone resorption-in hyperparathyroidism, osteoblastic malignant lesions, rickets, hemolytic anemia in children, and in normal infants in the growth zone of bone in the tibia. They were not seen in senile and postmenopausal osteoporosis. Recognition of osteoblasts and osteoclasts in smear preparations from aspirated bone marrow material may serve as a diagnostic aid in metabolic bone diseases. The differentiation of osteoblasts from neoplastic cells is important in cases in which metastatic cancer of the bone is suspected and x-ray findings are inconclusive.