Myxoid Liposarcoma

Clinical

Rare <20 years, very rare <10 years of age
- Myxoid liposarcoma is the most common type under age 20
- Good prognosis, with similar behavior to adults
Most common in thigh
- Other sites include popliteal, groin, buttock
- Rare in retroperitoneum
  - May metastasize to this site
  - Apparent primary retroperitoneal tumors appear to be atypical lipomatous tumors genetically (de Vreeze)
- Very rare in subcutis
Prognosis
- Low cellularity tumors may metastasize, but only rarely
- Cellular (25% of area) tumors frequently metasasize
  - Rate of metastasis is related to proportion of tumor that is cellular
  - Metastases frequently delayed
    - Median time 5-6 years
    - Most frequent sites are retroperitoneum, mediastinum, spine