Supporting a diagnosis of well-differentiated liposarcoma/atypical lipomatous tumor
The test includes a charge for technical application and professional interpretation of results.
Fluorescence In Situ Hybridization (FISH)
Atypical Lipomatous Tumor
Carboxypeptidase M (CPM)
Lipoma
Osteosarcoma
The test includes a charge for technical application and professional interpretation of results.
Tissue
Advise Express Mail or equivalent if not on courier service.
If sending a paraffin block, ship with an icepack during warm seasons.
1. A pathology report is required for testing to be performed. If not provided, appropriate testing and/or interpretation may be compromised or delayed. Acceptable pathology reports include working drafts, preliminary pathology, or surgical pathology reports.
2. The following information must be included in the report provided:
-Patient name
-Block number - must be on all blocks, slides, and paperwork
-Date of collection
-Tissue source
3. A reason for testing must be provided. If this information is not provided, an appropriate indication for testing may be entered by Mayo Clinic Laboratories.
Submit only 1 of the following specimens:
Preferred:
Specimen Type: Tissue block
Collection Instructions: Submit a formalin-fixed, paraffin-embedded tumor tissue block. Blocks prepared with alternative fixation methods are not accepted; provide fixation method used.
Acceptable:
Specimen Type: Tissue slides
Slides: 1 Hematoxylin and eosin-stained and 2 unstained
Collection Instructions: Submit 1 slide stained with hematoxylin and eosin and 2 consecutive, unstained, positively charged, unbaked slides with 4 to 5-micron-thick sections of the tumor tissue.
Slides: 1 hematoxylin and eosin-stained and 1 unstained
Decalcified specimens | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Tissue | Ambient (preferred) | ||
Refrigerated |
Supporting a diagnosis of well-differentiated liposarcoma/atypical lipomatous tumor
The test includes a charge for technical application and professional interpretation of results.
Differential diagnosis of well-differentiated liposarcoma/atypical lipomatous tumor:
The histological discrimination of well-differentiated liposarcoma/atypical lipomatous tumor (WDL/ALT) from lipoma can be diagnostically challenging. However, standard cytogenetic identification of ring and giant rod chromosomes strongly support the diagnosis of WDL/ALT. These abnormal chromosomes are mainly composed of amplified sequences derived from chromosome bands 12q13-15 and contain several amplified genes including MDM2, CPM, CDK4, and TSPAN31. MDM2 is amplified in greater than 99% of WDL and up to 30% of other types of sarcomas.
Differential diagnosis of osteosarcoma:
The histological discrimination of parosteal or low-grade central osteosarcoma from other morphologically similar, but clinically distinct entities, can be difficult. Amplification of genomic material derived from chromosome 12q13-15, which contains several genes including MDM2, has been shown to be a recurrent finding in a large proportion (67-100%) of parosteal and central low-grade osteosarcomas. Therefore, the detection of MDM2 gene amplification by fluorescence in situ hybridization may be a useful adjunct to support a diagnosis of low-grade central or parosteal osteosarcoma in the proper histopathologic context. Amplifications of 12q13-15 (including MDM2) are less common in conventional high-grade osteosarcoma, estimated to occur in approximately 5% to 10% of tumors.
An interpretive report will be provided.
Differential diagnosis of well-differentiated liposarcoma/atypical lipomatous tumor:
A neoplastic clone is detected when the percentage of cells with an abnormality exceeds the normal reference range for the MDM2 fluorescence in situ hybridization (FISH) probe (positive result). A positive result is consistent with amplification of the MDM2 gene locus (12q15) and supports the diagnosis of well-differentiated liposarcoma/atypical lipomatous tumor (WDL/ALT). A negative result is consistent with absence of amplification of the MDM2 gene locus (12q15). However, negative results do not exclude the diagnosis of WDL/ALT. Amplification varies in individual tumors and among different cells in the same tumor.
Differential diagnosis of osteosarcoma:
A positive result is consistent with amplification of the MDM2 gene locus (12q15) and supports the diagnosis of parosteal osteosarcoma or low-grade central osteosarcoma. A negative result indicates an absence of amplification of the MDM2 gene locus (12q15). However, negative results do not exclude the diagnosis of low-grade central osteosarcoma or parosteal osteosarcoma.
This test is not approved by the US Food and Drug Administration, and it is best used as an adjunct to existing clinical and pathologic information.
Fixatives other than formalin (eg Prefer, Bouin) may not be successful for fluorescence in situ hybridization (FISH) assays; Optimum fixation should be performed in 10% neutral buffered formalin. Non-formalin-fixed samples will be rejected.
Paraffin-embedded tissues that have been decalcified may not be successful for FISH analysis. Decalcified samples will be rejected.
1. Erickson-Johnson MR, Seys AR, Roth CW, et al. Carboxypeptidase M: a biomarker for the discrimination of lipoma from liposarcoma. Mod Pathol. 2009;22(12):1541-1547
2. Jacob E, Erickson-Johnson MR, Wang X, et al. Assessment of MDM2 amplification using fluorescence in situ hybridization on paraffin-embedded tissue discriminates atypical lipomatous tumors from lipomas. Mod Pathol. 2006;19:13A
3. He X, Pang Z, Zhang X, et al. Consistent Amplification of FRS2 and MDM2 in Low-grade Osteosarcoma: A genetic study of 22 cases with clinicopathologic analysis. Am J Surg Pathol. 2018;42(9):1143-1155
4. Duhamel LAE, Ye H, Halai, D, et al. Frequency of Mouse Double Minute 2 (MDM2 ) and Mouse Double Minute 4 (MDM4) amplification in parosteal and conventional osteosarcoma subtypes. Histopathology. 2012;60(2):357-359
5. Dujardin F, Binh MBN, Bourvier C, et al. MDM2 and CDK4 Immunohistochemistry Is a Valuable Tool in the Differential Diagnosis of Low-Grade Osteosarcomas and Other Primary Fibro-Osseous Lesions of the Bone. Mod Pathol. 2011;24(5):624-637
6. Fletcher DM, Bridge JA, Hogendoorn PCW, Mertens F eds. WHO Classification of Tumours of Soft Tissue and Bone. International Agency for Research on Cancer; 2013
This test is performed using commercially available MDM2 (12q15) and chromosome 12 centromere (D12Z3) probes. Formalin-fixed, paraffin-embedded tissues are cut at 4 to 5 microns and mounted on positively charged glass slides. The selection of tissue and the identification of target areas on the hematoxylin and eosin (H and E)-stained slide is performed by a pathologist. Using the H and E-stained slide as a reference, target areas are etched with a diamond-tipped etcher on the back of the unstained slide to be assayed. The probe set is hybridized to the appropriate target areas and 2 technologists each analyze 30 interphase nuclei (60 total) per probe set with the results expressed as a ratio MDM2:D12Z3 signals.(Unpublished Mayo method)
Monday through Friday
This test was developed using an analyte specific reagent. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.
88377
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
JMDMF | MDM2 (12q15) Amp, FISH, Tissue | 93808-4 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
616054 | Result Summary | 50397-9 |
616055 | Interpretation | 69965-2 |
616057 | Result | 62356-1 |
616058 | Reason for Referral | 42349-1 |
616059 | Specimen | 31208-2 |
616060 | Source | 31208-2 |
616061 | Tissue ID | 80398-1 |
616062 | Method | 85069-3 |
616063 | Additional Information | 48767-8 |
616064 | Disclaimer | 62364-5 |
616065 | Released By | 18771-6 |
Change Type | Effective Date |
---|---|
New Test | 2024-11-04 |