Pleomorphic Liposarcoma
Definition
- Cellular, pleomorphic sarcoma with lipoblasts
Diagnostic Criteria
- Pleomorphic, cellular sarcoma
- Most show features of pleomorphic MFH
- May show other patterns
- Fibrosarcoma
- Hemangiopericytoma
- Rhabdoid tumor
- Chondrosarcoma
- Epithelioid differentiation
- Lipoblasts must be present
- Cytoplasmic vacuole or vacuoles
- Must be sharply defined
- Must indent and distort nucleus
- May be focal or widespread
- S100 may highlight lipoblasts
- May contain cytoplasmic eosinophilic globules
- Cytoplasmic vacuole or vacuoles
- Mature fat cells not present
- Overrun fat at periphery must be excluded
- May have myxoid background
- Pleomorphic myxoid liposarcoma has been reported in young patients
(Alaggio)
- 12 of 82 liposarcomas age 22 and under
- Typical myxoid pattern merging with hypercellular foci with marked pleomorphism and increased, atypical mitotic figures
- 70% mortality within 36 months
- Lacks CHOP translocations of usual myxoid type
- Not clear if this should be considered a variant of myxoid type, pleomorphic type, a mixed type, or a separate type
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting: August 4, 2007
Updates: April 20, 2008; May 25, 2009
