Alternate Test Names:
FISH evaluation for MDM2 amplification has been shown to be a useful tool in the diagnosis of lipomatous neoplasms; specifically, well-differentiated liposarcomas, atypical lipomatous tumors, and dedifferentiated liposarcomas containing cytogenetic alterations of the 12q13-15 region. MDM2 is a gene in this genomic region that is frequently amplified in these tumor types. In contrast, benign lipomas and lipocytic tumors as well as most other non-lipomatous sarcomas and mesenchymal neoplasms have been shown to be negative for MDM2 amplification.
Testing for MDM2 amplification by FISH therefore aids in the pathologic differential diagnosis of lipomatous/dedifferentiated liposarcomas versus nonlipocytic sarcomas and mesenchymal neoplasms; specifically, when the histologic differential diagnosis is lipoma versus well-differentiated liposarcoma, the presence of MDM2 amplification would be in keeping with liposarcoma. Additionally, when the differential includes dedifferentiated liposarcoma versus sarcoma, NOS, as well as other sarcoma types, the presence of MDM2 amplification also suggests a lipocytic origin. Finally, non-amplified, but polysomic MDM2 and SE12 can be seen in cases of pleomorphic lipoma.
Probe type: Dual color enumeration
Organ: Soft Tissue
Disease State: Spindle Cell Tumors / Sarcoma Subtyping
CPT Code(s): 88374 (reference only; CPTs may vary)
Turnaround Time: Within 3-4 business days of receipt
Schedule: Monday - Friday
• Formalin-fixed, paraffin-embedded tissue block or cell block - OR -
• Minimum of 5 unstained slide cut at 4µm for each test requested