I was just thinking and encountered this same topic earlier this week... After the administration of contrast material, low grade liposarcomas might enhance minimally or not at all. + it also depends on how myxoid or heterogeneous they are... if there is alot of necrosis or cystic spaces, there may be strange patterns of enhancement or again,none at all.
in theory, what I've encountered is that with high malignancy grade, there is parallel increase in contrast enhancement, albeit heterogeneous. what is your experience?
FROM THE PATH STANDPOINT
OUR ONCOLOGITS RELY VERY HEAVILY NOW
ON IMMUNO HISTO TYPING / MDM2 AND CDK4
APPARENTLY THEIR FEELING IS THAT SOME BIOPSY MR GUIDED IF FEASIBLE
ON THE POORLY ENHANCING AREAS
IS COUPLED WITH THIS MURINE AG TEST
IF POSITIVE YOU ARE DEFINITELY IN LOW GRADE LIPOSARC ADN TREATA CCORDINGLY RESECT F/U ETC
THERE IS SOME DEBATE ABOUT THE EXCISION MARGINS
YOU MIGHT REPEAT THE BIOPSY / ANOTHER ENHANCING AREA AND IF NEG FEEL GOOD
WHEN NOTHING ENHANCES
AND THE INNER STRUCTURE IS INHOMOGENEOUS
CLASSIC IN ATYPICAL LIPOMA WITH INNER STRANDS
WHAT DO WE DO?
YOU POINT IS EXCELLENT ABOUT TUMOR AGGRESSIVENESS LINKED TO ENHANCEMENT
ANY ENHANCING AREA MUST BE BIOPSIED AND MDMD2 CDK4 APPARENTLY IS THE WAY TO GO
THANK YOU VERY MUCH W
Detection of MDM2-CDK4 Amplification by Fluorescence In Situ Hybridization in 200 Paraffin-embedded Tumor Samples: Utility in Diagnosing Adipocytic Lesions and Comparison With Immunohistochemistry and Real-time PCR.
Sirvent N, Coindre JM, Maire G, Hostein I, Keslair F, Guillou L, Ranchere-Vince D, Terrier P, Pedeutour F.
*Laboratory of Solid Tumors Genetics, CNRS UMR 6543 †Department of Pediatry, Nice University Hospital, Nice ‡Department of Pathology, Institut Bergonié and University Victor Ségalen, Bordeaux ∥Department of Pathology, Centre Léon Bérard, Lyon ¶Department of Pathology, Institut Gustave Roussy, Villejuif, France §Department of Pathology, University Institute of Pathology, Lausanne, Switzerland.
Am J Surg Pathol. 2007 Oct;31(10):1476-1489. Abstract quote
Atypical lipomatous tumor/well-differentiated liposarcomas and dedifferentiated liposarcomas are characterized by the amplification of MDM2 and CDK4 genes.
To evaluate the accuracy of fluorescence in situ hybridization (FISH) analysis in the differential diagnosis of adipose tissue tumors, we investigated MDM2-CDK4 status by FISH, real-time polymerase chain reaction (PCR) [quantitative PCR (Q-PCR)] and immunohistochemistry (IHC) in a series of 200 adipose tumors.
First, we evaluated MDM2-CDK4 amplification and expression in a series of 94 well-defined adipose tissue tumors. Results showed that FISH was interpretable in 45 of 50 cases (90%), and was more specific and sensitive than Q-PCR and IHC. We then used the same techniques as complementary diagnostic tools in a series of 106 adipose and soft tissue tumors of unclear diagnosis to distinguish between (i) lipomas and atypical lipomatous tumor/well-differentiated liposarcomas, (ii) malignant undifferentiated tumors and dedifferentiated liposarcomas, and (iii) a variety of benign tumors and liposarcomas.
Our results indicate that although helpful, IHC alone is often insufficient to solve diagnostic problems. FISH and Q-PCR methods gave concordant results and were equally informative in most cases. However, the proportion of noninterpretable cases was slightly higher with FISH than with Q-PCR. When tumor cells represented a minor component of the tumor tissue, such as with inflammatory tumors, FISH was more powerful than Q-PCR by allowing visualization of individual cells.
In conclusion, we recommend that the evaluation of MDM2-CDK4 amplification using FISH or Q-PCR be used to supplement IHC analysis when diagnosis of adipose tissue tumors is not possible based on clinical and histologic information alone.