Lymphoblastic Leukemia

Osteonecrosis is a rare and serious complication that can be developed during or after treatment for acute lymphoblastic leukemia (ALL). The incidence of symptomatic osteonecrosis related to ALL treatment is 1.6-9.3%. High-dose steroid therapy is the major risk factor for osteonecrosis. The pathophysiology is unclear. It is thought that osteonecrosis occurs due to steroid use causing thromboembolism in sinusoidal veins leading to hypoxia resulting in decreased osteoblast activity and increased osteoclast activity. Magnetic resonance imaging is the most sensitive diagnostic method in early period. We present two girls, 15 and 14-year-old, in whom osteonecrosis developed during ALL maintenance therapy