Skeletal abnormalities such as hypertrophic callus formation and "popcorn" calcifications are rare radiological findings of osteogenesis imperfecta, causing tumor-like appearances on imaging. We report on a 7-year-old girl with osteogenesis imperfecta presenting with hepatomegaly and palpable lymphadenopathy in the left inguinal region on physical examination. Computed tomography examination revealed a high-density mass-like lesion of the manubrium sterni. Ultrasonography and a lateral roentgenogram of the chest verified that this was a pseudomass caused by a bowed sternal manubrium.