Figure 1.

A 4-month-old girl with lipoblastoma of the left arm presented with swelling. (a) Plain film of the left arm reveals a soft tissue mass (arrows) in the posterolateral portion of the arm with no abnormalities in the adjacent humerus. (b) Sagittal MRI views of the left arm. A well-circumscribed, heterogeneous mass is seen within the left triceps, separate from the humerus and subcutaneous tissues. On turbo short tau inversion recovery (STIR) image (I), there is no surrounding edema – an indicator of slow growth. On T1W SE image (II), areas of high signal intensity are seen within the lesion, suggesting presence of fat which shows however slightly lower signal intensity than that of subcutaneous fat and minor enhancement on T1W spin echo post-contrast image (III). (c) Photomicrograph demonstrating a lobule within the lesion composed of adipocytes and numerous lipoblasts with central ‘scalloped’ nucleus and vacuolated cytoplasm. There is no nuclear atypia (H&E, original magnification ×100).