Pleomorphic sarcoma is a high grade sarcoma of lipogenic (fatty/adipose) origin. It is a type of liposarcoma that has some lipoblasts admixed with mostly high grade pleomorphic appearing spindle cells.
Represents 5 to 10% of all liposarcomas
No predilection for any race or sex
Usually affecst patients between the fifth to seventh decade
Rare in younger ages
Associated with post radiation treatment in neurofibromatosis.
Undifferentiated pleomorphic sarcoma
Slowly growing tumor
No predilection for any sex or race
Less than 10% of all soft tissue sarcomas
Does not have a strong locational predilection
Most commonly intramuscular or in other deep sites
Occasionally occurs in subcutaneous tissue
No specific radiological features
May reveal a soft tissue mass
Often heterogenous with density similar to muscle
Large mass with heterogeneous signal intensity (Fig. 1, 2)
Strong enhancement post gadolinium (suggestive of malignant process)
Areas of necrosis and hemorrhage
Usually it is very difficult to detect any fat within the mass on an MRI
Fig. 1, 2 Axial MRI of shoulder shows a lesion in the subcutaneous tissue along the postermedial border of the scapula.
Often large (8-10 cm), may up to 20 cm; multiodular (Fig. 3)
Areas of hemorrhage and necrosis common
Usually has a sarcomatous fleshy appearance
Sometimes has partly or wholly myxoid component
May contain white-yellow coloration
Fig. 3 Gross Pathology: Photo of a gross specimen.
Well circumscribed, but non-encapsulated
Cellular in nature
Tumor necrosis common
Moderately to markedly pleomorphic (Fig. 4 and 5)
Large cells and cytologically malignant
Nuclei are elongate, round or bizarre
Mitosis 10 high per field
Some contain identifiable lipid vacuoles
Indent the nucleus
No mature fat cells
Fig. 4 Microscopic: Intermediate and high (Fig. 5) power magnification show prominent pleomorphism, and many lipid vacuoles; cells are large and multinucleated. The lipoblasts are pleomorphic.
Smooth muscle actin
High risk for local recurrence (wide excision option for treatment)
High risk for metastasis
Less than 60% survival over 5 years
Poor prognostic factors:
Deep to fascia
Larger than 5 cm
Wide excision (Fig. 6 and 7)
Radiotherapy and chemotherapy
Chemotherapy may be controversial
Fig. 6 Intraoperative photograph of skin incisions to remove a pleomorphic liposarcoma from the trapezius area. The patient had a previous biopsy through a transverse incision. Transverse incisions should rarely be used to biopsy a tumor.
Fig. 7 Photograph shows the tumor and the biopsy tract.