Intraosseous Lipoma of the Proximal Radius with Extra Osseous Extension leading to Posterior Interosseous Nerve Compression: HRUS Diagnosis

INTRODUCTION: Benign musculoskeletal lipomatous lesions are common in both soft tissue and bone. Imaging features of benign lipomatous lesions are often pathognomonic. Ultrasound (US) has been used to examine both soft tissue and bone tumors, allowing targeted CT or MRI examination of the region of interest. CASE REPORT: A 46-year-old female presented with a four year history of palpable mass lesion just below the lateral aspect of right elbow with clinical evidence of posterior interosseous nerve compression. X-ray showed the presence of a radiolucency mass in relation to radius. HRUS demonstrated a hyperechoic mass in soft tissue with a focal irregularity in bony cortex of radius. The mass lesion compressed the posterior interosseous nerve. CONCLUSION: Although CT and MRI diagnose them accurately, but ultrasound characteristics are also conclusive for extra osseous component. This case highlights the importance of HRUS for evaluation of musculoskeletal tumors and any secondary changes in a readily available cost effective dynamic modality and thus guide for treatment planning accordingly.