PMID- 26146760
OWN - NLM
STAT- MEDLINE
DCOM- 20151214
LR  - 20220317
IS  - 1532-0979 (Electronic)
IS  - 0147-5185 (Linking)
VI  - 39
IP  - 10
DP  - 2015 Oct
TI  - MDM2 Amplification in Problematic Lipomatous Tumors: Analysis of FISH Testing 
      Criteria.
PG  - 1433-9
LID - 10.1097/PAS.0000000000000468 [doi]
AB  - To discriminate lipomas from atypical lipomatous tumor/well-differentiated 
      liposarcoma (ALT/WDL) we perform fluorescence in situ hybridization (FISH) for 
      MDM2 amplification in several problematic situations: "lipomas" >10 cm, lesions 
      with equivocal atypia, recurrent "lipomas," all retroperitoneal/pelvic/abdominal 
      "lipomas", and in cases not fitting the above criteria but having worrisome 
      clinical or radiologic features. To ascertain the validity of these criteria, we 
      have reviewed our experience with 301 consecutive differentiated lipomatous 
      tumors in which the diagnosis of ALT could not be established on the basis of 
      histologic sections and in which FISH was performed on the basis of the above 
      criteria. The final diagnosis was based on MDM2 amplification status. Given the 
      nature of this study to evaluate difficult lesions, most cases included (74%) 
      were received in consultation. This enhanced our study series for borderline 
      cases, and the data presented may not be generalizable to adipocytic tumors seen 
      outside a subspecialty setting. Of 301 cases, 108 proved to be ALT/WDL (36%). The 
      most common test indication was size >10 cm (n=187), followed by equivocal atypia 
      (n=145), retroperitoneal/pelvic/abdominal location (n=86), recurrence (n=33), and 
      clinical concern (n=12). Of the tumors >10 cm, 68 (36%) proved to be ALT/WDL, 
      whereas the remainder were interpreted as lipoma or its variants (eg, spindle 
      cell or pleomorphic lipoma). The 2 groups did not differ statistically in size, 
      although ALTs consistently occurred in patients above 50 years of age. Of the 
      cases with equivocal atypia, 72 (50%) proved to be ALT/WDL. Those in the 
      retroperitoneum/abdomen/pelvis were ALT/WDL in 30 cases (35%), and those that had 
      recurred were ALT in 18 cases (55%). Recurrence, atypia, and having multiple 
      indications for testing were more common in ALT than in benign lesions (P=0.02, 
      0.0001, 0.0012, respectively). No ALT/WDL occurred in the hands and feet, and 
      only a single ALT/WDL was superficial (1 ALT/WDL vs. 60 lipoma/spindle cell or 
      pleomorphic lipoma). Small (<10 cm) retroperitoneal tumors without additional 
      features were always benign (n=9). On the basis of our results, FISH testing is 
      recommended for: (1) recurrent lesions; (2) deep extremity lesions that are >10 
      cm in patients over 50 years of age; (3) in cases with equivocal atypia; (4) in 
      lesions of the retroperitoneum/pelvis/abdomen, and in special clinical situations 
      as directed by treating clinicians. Testing is low yield in superficial lesions, 
      in small extremity lesions without additional indicators for testing, in large 
      extremity lesions without additional features in patients under the age of 50, 
      and in lesions arising in the hands/feet. More evidence is needed regarding 
      testing in small retroperitoneal lesions without additional features. By adopting 
      these criteria, we could have avoided testing 74 cases, missing a single 
      superficial ALT/WDL.
FAU - Clay, Michael R
AU  - Clay MR
AD  - Department of Pathology, Emory University Hospital, Atlanta, GA.
FAU - Martinez, Anthony P
AU  - Martinez AP
FAU - Weiss, Sharon W
AU  - Weiss SW
FAU - Edgar, Mark A
AU  - Edgar MA
LA  - eng
PT  - Journal Article
PT  - Validation Study
PL  - United States
TA  - Am J Surg Pathol
JT  - The American journal of surgical pathology
JID - 7707904
RN  - 0 (Biomarkers, Tumor)
RN  - EC 2.3.2.27 (MDM2 protein, human)
RN  - EC 2.3.2.27 (Proto-Oncogene Proteins c-mdm2)
SB  - IM
MH  - Adult
MH  - Aged
MH  - Aged, 80 and over
MH  - Biomarkers, Tumor/*genetics
MH  - Diagnosis, Differential
MH  - Female
MH  - *Gene Amplification
MH  - Genetic Predisposition to Disease
MH  - Humans
MH  - *In Situ Hybridization, Fluorescence
MH  - Lipoma/*genetics/pathology/surgery
MH  - Male
MH  - Middle Aged
MH  - Neoplasm Recurrence, Local
MH  - Phenotype
MH  - Predictive Value of Tests
MH  - Proto-Oncogene Proteins c-mdm2/*genetics
MH  - Reproducibility of Results
MH  - Risk Factors
MH  - Tumor Burden
MH  - Young Adult
EDAT- 2015/07/07 06:00
MHDA- 2015/12/15 06:00
CRDT- 2015/07/07 06:00
PHST- 2015/07/07 06:00 [entrez]
PHST- 2015/07/07 06:00 [pubmed]
PHST- 2015/12/15 06:00 [medline]
AID - 10.1097/PAS.0000000000000468 [doi]
PST - ppublish
SO  - Am J Surg Pathol. 2015 Oct;39(10):1433-9. doi: 10.1097/PAS.0000000000000468.