Mastocytosis and the Bone: Observational Study

Mastocytosis is a rare disorder caused by the accumulation of clonal, neoplastic mast cells and their precursors. Mastocytosis occurs in about 1/10,000 individuals, and it is divided into cutaneous and systemic disease. Skeletal manifestations are one of the frequent findings of systemic mastocytosis (SM), occurring in about 50% of patients. Bone abnormalities reported in SM include osteopenia, osteoporosis, pathologic fractures, skeletal deformities, focal osteosclerosis, and osteolytic lesions. The variability in presentation of bone disease is still unexplained. Furthermore, bone manifestations of SM are often asymptomatic, and therefore, a large proportion of patients remains undiagnosed. Systemic mastocytosis has long been identified as a potential cause of secondary osteoporosis. Patients with SM have a higher risk of bone fragility that is not always linked to the bone mineral density (BMD). In fact, fragility fractures are associated not only with osteoporosis but also with osteopenia, osteosclerosis, or lytic lesions. Therefore, BMD alone is not sufficient to predict the risk of new fractures and to make the clinical decision of whom to treat preventively.