The Hyperechoic Nodules in Lipedema Are Not All the Same: Description of Criteria and Their Qualitative Patterns

Lipedema is characterized by symmetrical accumulation of subcutaneous fat in the lower and upper limbs, sparing the trunk, feet and hands. Although diagnosis is primarily clinical, ultrasound has proven to be a valuable, non-invasive, reproducible, and cost-effective tool for the assessment of lipedema. Ultrasound (US) facilitates diagnosis through quantitative evaluation of subcutaneous tissue thickness and enables qualitative Lipedema Dermal and Hypodermal Classification (LDHC), with morphological changes. The presence of hyperechoic nodules in patients with lipedema has been previously described and classified as LDHC 3; recently, a case report analyzing the microscopic features of such nodules demonstrated hemorrhagic areas and steatonecrosis, resulting from disorganized hypodermal expansion leading to increased pressure within the subcutaneous compartment—causing hypoxia and stimulating immature neovascularization (fragile wall, predisposing to hemorrhage). However, these nodules are not uniform and exhibit different morphologies, enabling subclassification. The first type presents with poorly defined margins; the second is well-defined margins; the third has an anechoic area, and the fourth shows a faint posterior shadow. These different nodule presentations in lipedema may be correlated with evolutionary stages or previously described clinical presentations, requiring future correlation with pathological anatomy or other diagnostic methods.