Myogenic Differentiation and Histologic Grading Are Major Prognostic Determinants in Retroperitoneal Liposarcoma

Abstract

The aim of the present work was to improve the understanding of the impact of malignancy grade and myogenic/rhabdomyoblastic differentiation on the natural course of retroperitoneal liposarcoma. All consecutive patients affected by primary well-differentiated (WD)/dedifferentiated (DD) retroperitoneal liposarcoma, surgically treated at our institution between January 2002 and December 2011, were retrospectively evaluated. Tumors were stained for mdm2 and 5 myogenic markers (smooth muscle actin-α, h-caldesmon, calponin, desmin, myogenin). The French National Federation of the Centers for the Fight Against Cancer (FNCLCC) grading system was applied. Overall survival, crude cumulative incidence of local recurrence, and distant metastases were calculated. Multivariable analyses were carried out. A total of 144 patients were identified. Median follow-up was 68 months (interquartile range: 46 to 104 mo). Fifty-two patients were affected by WD/G1 and 92 by DD liposarcoma. Among the latter, 60 were grade G2 and 32 G3. Myogenic differentiation was present in 54 cases (8/52 WD/G1, 27/60 DD/G2, 18/32 DD/G3). Seven cases had a rhabdomyoblastic DD component (1/60 DD/G2 and 6/32 DD/G3). Five-year overall survival rates were 93%, 57%, and 21% for WD/G1 liposarcoma, G2 DD, and G3 DD liposarcoma, respectively, and 75%, 42%, and 29% for liposarcoma without myogenic differentiation, with myogenic differentiation, with rhabdomyoblastic differentiation, respectively (P<0.001). Of note, 5/6 patients affected by G3 DD liposarcoma with a rhabdomyoblastic component died within 8 months. FNCLCC grade and myogenic differentiation significantly predicted the outcome of retroperitoneal liposarcoma. These should be factored into treatment decision-making and possibly used to stratify patients in clinical trials.

Osteogenic differentiation in dedifferentiated liposarcoma: a study of 36 cases in comparison to the cases without ossification

“…However, the follow‐up periods of this study might not be long enough to assess true life outcomes. High histological grade and a retroperitoneal tumour location have been reported repeatedly to be associated with worse outcomes in DDLPS . In our study, histological grade was the most important prognostic factor, while retroperitoneal tumour location was related only to shorter LRFS.…”

“…It is also widely recognised that DDLPS sometimes exhibits heterologous differentiation . Myogenic differentiation is the most common type, and the impact of myogenic differentiation on prognosis has been investigated . Conversely, formation of bone tissue has been reported in 0.6–29% of cases in large studies of DDLPS, and the bone formation has usually been described as either ‘osteosarcomatous differentiation’ or ‘metaplastic bone formation’ according to histological analyses.…”

Oncology outcomes in Retroperitoneal sarcomas: Prognostic factors in a Retrospective Cohort study

“…Low-grade tumors carry the risk of local recurrence, but rarely cause distant metastases. 12,13 The objective of this review is to evaluate the most important…”

Pericytic mimicry in well-differentiated liposarcoma/atypical lipomatous tumor

“…Although somewhat limited in number, our cases followed a typical disease course for WDLPS / ALT, characterized by local recurrence in 2/7 cases (28.5%). Of note, Gronchi et al recently found that myogenic differentiation was associated with a poor prognosis in retroperitoneal liposarcoma 28 . However this study examined both well-differentiated and dedifferentiated tumors, and included both markers of smooth and skeletal muscle differentiation.…”