Table 1.
Summary of diagnostic and prognostic features of select adipocytic neoplasms.
| Tumor Type | Useful Diagnostic IHC Markers | Characteristic Genomic Aberrations | Behavior |
|---|---|---|---|
| Spindle cell/pleomorphic lipoma | RB1 loss; variable expression of CD34, desmin, S100 | 13q14 deletion (RB1) | Benign |
| Atypical spindle cell/pleomorphic lipomatous tumor (ASCLT/APLT) | RB1 loss (50–70%); variable expression of CD34, desmin, S100 | 13q14 deletion (RB1) | Benign; local recurrence in 10–15% if incompletely excised |
| Atypical lipomatous tumor (ALT)/Well-differentiated liposarcoma (WDLPS) | Expression of MDM2 and/or CDK4 | 12q13–15 high-level amplification (MDM2, CDK4) | Locally aggressive; risk of dedifferentiation |
| Dedifferentiated liposarcoma | Expression of MDM2 and/or CDK4 | 12q13–15 high-level amplification (MDM2, CDK4) | Malignant |
| Myxoid liposarcoma | DDIT3 expression in high-grade cases | FUS-DDIT3 gene fusion | Malignant |
| Pleomorphic liposarcoma | None | None | Malignant |
| Myxoid pleomorphic liposarcoma | RB1 loss (subset) | Complex chromosomal alterations | Highly malignant |