[54] Are Peripheral Pure Pleomorphic Sarcomas with MDM2 Amplification Dedifferentiated Liposarcomas?

Sophie Le Guellec, Agnes Neuville, Frederic Chibon, Dominique Ranchere-Vince, Frederique Larousserie, Philippe Terrier, Jean-Michel Coindre. Institut Claudius Regaud, Toulouse, France; Institut Bergonié, Bordeaux, France; Centre Léon Bérard, Lyon, France; CHU Cochin, Paris, France; Institut Gustave Roussy, Paris, for the French Sarcoma Group, France

Background: Dedifferentiated liposarcoma (DDLPS) has been defined as a tumor composed of well-differentiated liposarcoma (WDLPS) associated with a nonlipogenic undifferentiated sarcoma and is genetically characterized by a 12q13-14 amplicon with MDM2 amplification. Some peripheral (extremities, trunk wall, head and neck) undifferentiated pleomorphic sarcomas without areas of WDLPS present a MDM2 amplification (PUPS-MDM2 pos).The purpose of this study is to address whether they are true DDLPS or not.
Design: The present study compared clinical data, histology, genomic profile (array-CGH) and follow-up (overall survival-OS, metastasis-free survival-MFS and local recurrence-free survival-LRFS) in PUPS-MDM2 pos and peripheral conventional (with areas of WDLPS) DDLPS (PC-DDLPS) patients retrieved from 1-the French sarcoma network RRePS (http://www.rreps.sarcomabcb.org) for systematic histological review (2010 and 2011) and 2-the Conticabase (http://www.conticabase.sarcomabcb.org)(1980 to 2011). We only considered patients with a resection of the primary tumor and with adequate sampling.
Results: We collected respectively 10 PUPS-MDM2 pos and 120 PC-DDLPS (which accounted for 25.3% of all DDLPS) in RRePS and 10 PUPS-MDM2 pos and 80 PC-DDLPS in the Conticabase. Follow–up was available for 20 PUPS-MDM2 pos and 80 PC-DDLPS. Clinical characteristics and follow-up are shown in Table. Array-CGH performed in 20 PUPS-MDM2 pos and in 20 PC-DDLPS showed a typical profile of DDLPS with a 12q13-14 amplicon.

  PUPS-MDM2 posPC-DDLPSp-value
N 2080 
Morphological features of dedifferentiated componentSpindle/pleomorphic15400.194
Age at diagnosis (years)Median (range)77 (49-90)67 (18-88)0.006
Tumor size (cm)Median (range)9.75 (2.5-20)13 (2.5-50)0.077
Tumor localizationExtremities10510.423
 Trunk wall926 
Follow-up,yearsMedian (95%CI)22.9 (3.9-NA)28.8 (15.1-40.1) 
OS rate 0.799α0.867α0.203β
MFS rate 0.436α0.649α0.146β
LRFS rate 0.697α0.826α0.395β
αKaplan-Meier estimate at 2 years; βLog-rank test

Conclusions: Although PUPS-MDM2 pos occur in older patients, the similarities in the histologic features, genomic profiles of PUPS-MDM2 pos and PC-DDLPS suggest that PUPS-MDM2 pos may be best positioned as part of the spectrum of DDLPS rather than as a distinct entity.
Category: Bone & Soft Tissue

Tuesday, March 5, 2013 1:00 PM

Poster Session IV # 25, Tuesday Afternoon


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