Distant metastasis in retroperitoneal dedifferentiated liposarcoma is rare and rapidly fatal: a clinicopathological study with emphasis on the low-grade myxofibrosarcoma-like pattern as an early sign of dedifferentiation

Abstract

The metastatic incidence of retroperitoneal dedifferentiated liposarcoma is comparatively lower than other pleomorphic sarcomas, varying widely from 1 to 18%. Low-grade dedifferentiation resembling low-grade fibrosarcoma has been recently accepted as part of the morphologic spectrum of dedifferentiated liposarcoma and was reported to have similar metastatic and survival rates to its high-grade counterpart. We sought to determine the metastatic incidence of retroperitoneal dedifferentiated liposarcoma, the clinicopathological features related to metastasis, and their postmetastatic behavior. Of all 354 retroperitoneal liposarcoma cases diagnosed at Memorial Sloan-Kettering Cancer Center during 1982-2003, we identified seven patients developing distant metastases, occurring in four females and three males, ranging from 35 to 73 years in age at presentation. They were all de novo dedifferentiated, while none of the well-differentiated liposarcoma or secondary dedifferentiated liposarcoma developed distant metastasis. Primary tumor sizes varied from 7.5 to 25 cm. All seven patients developing metastases contained Z50% dedifferentiated elements in the primary tumor, with a predominant morphology resembling myxofibrosarcoma in five cases. The metastatic sites included the lung in four patients, somatic soft tissue in two, and liver in one. The median metastasis-free survival was 48 months, with only two patients experiencing local recurrences before developing metastasis. Six patients died of disease at median follow-up of 53 months after diagnosis and only 5 months after their first metastases. In conclusion, retroperitoneal dedifferentiated liposarcoma have a low metastatic rate, which is strongly related to de novo dedifferentiated histology that usually constitutes a prominent component of the primary tumor. Irrespective of the grade dedifferentiated liposarcoma with myxofibrosarcoma-like features should be closely monitored. Once metastases occur, they tend to follow a rapidly fatal course. Modern Pathology (2005) 18, 976-984.

The role of histology, grading, location of tumour and ploidy in evaluation of outcome in patients with liposarcoma

“…Elgar and Goldblum, in their report on 20 cases of well-dedifferentiated and dedifferentiated liposar- [15]. Dedifferentiated liposarcomas associated with myxoid MFH-like or myxoid liposarcoma-like component were described subsequently by Hasegawa et al [16], and Huang et al [17]. Taking into consideration the above-mentioned findings, we stratified our well-differentiated and dedifferentiated liposarcomas according to the WHO classification, but we distinguished additionally a low-grade LPS group with histological picture corresponding to the tumours that Evans named as cellular atypical lipomatous tumours or low-grade dedifferentiated liposarcoma [18].…”

Soft-Tissue Sarcomas of the Abdomen and Pelvis: Radiologic-Pathologic Features, Part 1—Common Sarcomas:From the Radiologic Pathology Archives

“…Dedifferentiated liposarcoma with low-grade features is relatively indolent, and high-grade tumors often metastasize. In all, distant metastases arise in up to 18% of patients (22,23). At gross pathologic examination, dedifferentiated liposarcoma is a firm white or yellow solid nonlipogenic mass.…”

NAB2–STAT6 fusion types account for clinicopathological variations in solitary fibrous tumors

“…10,20,21 However, Doyle et al 22 have notified that STAT6 nuclear expression is driven by gene amplification and coamplified with CDK4 and MDM2 in a minor subset of dedifferentiated liposarcomas, a treacherous caveat liable to result in misdiagnosis of solitary fibrous tumors, given occasional presence of solitary fibrous tumorlike histology in dedifferentiated liposarcomas. 23,24 Aiming at better characterization of the relevance of STAT6 nuclear entry and NAB2-STAT6 fusion variants, we have comparatively analyzed the STAT6 immunoexpression and NAB2-STAT6 exon composition types and correlated the findings with clinicopathological features of a large cohort of recently accessioned thoracic, extrathoracic, and meningeal solitary fibrous tumors.…”