Bone marrow necrosis is an uncommon histologic finding of malignant diseases at presentation. Clinically it is characterized by pyrexia and severe bone pain, and heralds a poor prognosis if untreated. We report an unusual patient with asymptomatic bone marrow necrosis persisting for 10 mths, a hitherto undescribed length of time for this condition. The diagnosis of Philadelphia chromosome positive acute lymphoblastic leukemia was finally made after multiple bone marrow biopsies.