Choice of modality
- MRI is the imaging modality of choice in suspected lipoma, with superior sensitivity of distinguishing it from liposarcoma as well as mapping the surrounding anatomy.
- Ultrasonography of superficial soft tissues is the investigation of choice in stable superficial soft tissue masses of unknown origin, at least in flexion surfaces of large joints (groin, popliteal fossa, armpit and cubital fossa), to distinguish lipomas from for example aneurysms and lymph nodes.
If a lipoma is clinically suspected, ultrasound can often establish the diagnosis, but has a low accuracy, often warranting MRI anyways. MRI is the imaging of choice in soft tissue lumps that are growing, are over 5 cm in size, have deep location or are painful.[notes 2]