- More common in the deep soft tissues; subcutaneous examples are rare
- Most commonly seen in the lower limb of adults
- Tends to recur
- Metastases occur in approximately one third of cases
- Round cell liposarcoma is part of the spectrum of myxoid liposarcoma, and the presence of a round cell component is an adverse prognostic marker.
- Uniform stellate to spindled cells in a myxoid background
- The cells contain small vacuoles with rare mitoses
- Occasional lipoblasts can be seen, most commonly at the periphery of the tumor.
- The most characteristic and specific diagnostic feature is the universally present network of abundant small, curvilinear, branching capillaries, described as having a "chicken wire" or "crow's foot" appearance. The absence of these vessels effectively rules out the diagnosis of myxoid liposarcoma.
- Pools of mucin, sometimes resembling lymphangioma, are often present.
- Round cell change is the term used for more cellular areas with round to oval hyperchromatic nuclei and high nuclear:cytoplasmic ratios
- Round cell change is associated with a more aggressive course and less favorable prognosis.
- Tumors with both myxoid and round cell areas are known as either combined myxoid and round cell liposarcoma or high-grade myxoid liposarcoma.
- Pure round cell liposarcomas are extremely rare in the subcutis.