Cytogenetic analysis of a case of myxoid liposarcoma with cartilaginous differentiation

Myxoid liposarcoma with cartilaginous differentiation showing DDIT3 rearrangement

Myxoid liposarcoma (MLPS) is the second most common histologic subtype of liposarcoma. However, cartilaginous differentiation within MLPS is an extremely rare phenomenon, with only 7 cases of MLPS with cartilaginous differentiation reported to date. The majority of MLPS cases show the t(12;16)(q13;p11) translocation, resulting in the fused in sarcoma-DNA damage-inducible transcript 3 (FUS-DDIT3) fusion gene. This fusion gene as a hallmark of MLPS is very useful for differential diagnosis from other soft tissue sarcomas, and the associated protein, FUS-DDIT3, performs an important role in the phenotypic selection of targeted multipotent mesenchymal cells during oncogenesis. In this report, a case of MLPS with cartilaginous differentiation that occurred in the thigh of a 44-year-old woman is described. Histopathologically, the tumor was composed of a typical myxoid liposarcoma area and a mature hyaline cartilaginous area. Using fluorescence in situ hybridization analysis, rearrangement of the DDIT3 gene was detected in not only the liposarcomatous area but also in the chondrocytes of the cartilaginous area. Based on these findings, the cartilaginous differentiation area appears to be partially associated with oncogenesis through the specific fusion gene FUS-DDIT3.

Diagnosis, Classification, and Management of Soft Tissue Sarcomas

BACKGROUND

Soft tissue sarcomas are challenging to oncologists due to their unique character, the infrequency of their occurrence, and the difficulties in predicting outcomes. Advances in imaging, as well as improvements in surgical techniques and adjunctive treatment methods, have improved care for patients with these unusual disorders.

METHODS

The various types of soft tissue tumors are defined, and the statistics for the Orthopaedic Oncology Group in relation to them are reviewed and compared with literature references.

RESULTS

The overall survival rate for 1,220 tumors treated at our institute from June 1972 to June of 2001 was 72%, with a wide range. Patients with leiomyosarcomas, clear cell sarcomas, and malignant fibrous histiocytomas had a poorer survival rate, while those with fibrosarcomas, liposarcomas, and neurofibrosarcomas fared better. Outcome was affected by patient age, tumor anatomic site, tumor stage, and a history of recurrence.

CONCLUSIONS

Competent imaging, predictive immunological and genetic studies, improved surgery, and newer methods of adjunctive and neoadjunctive treatment should result in improvements in outcomes for patients with these tumors.

Focal Divergent Chondrosarcomatous Differentiation in a Primary Pleomorphic Liposarcoma and Expression of Transforming Growth Factor 3

A rare case of primary pleomorphic liposarcoma of the thigh with a myxoid component, in which divergent differentiation to a well-differentiated chondrosarcoma was focally present, is described. Presence of heterologous elements has mainly been recognized in the context of dedifferentiated liposarcomas. Few cases of benign mesenchymal tissue have also been reported in well-differentiated and myxoid liposarcomas, while divergent sarcomatous differentiation in liposarcomas appears to be also rare in the absence of dedifferentiation. Positive immunostaining of transforming growth factor-n, which seems to play a role in the formation of bone and cartilage, was demonstrated in our case. Review of the existing literature on the subject has been carried out.

Myxoid liposarcoma with heterologous components: dedifferentiation or metaplasia? A FISH-documented and CGH-documented case report

Heterologous differentiation in myxoid liposarcoma is a rare phenomenon. Few cases have been reported thus far, often without molecular assays, and the concept of "dedifferentiated" myxoid liposarcoma remains controversial. We describe a primary myxoid liposarcoma with chondroid and osseous components affecting the right thigh of a 27-year-old woman. We wondered whether these areas represented dedifferentiated components or simply metaplasia, and performed fluorescent in situ hybridization and array comparative genomic hybridization assays in the myxoid liposarcoma component and chondroid component. Fluorescent in situ hybridization analysis demonstrated a DDIT3 gene rearrangement in both components; array comparative genomic hybridization analysis did not detect any gain or loss of DNA regions in both components. Our results, demonstrating that both components have the same molecular alterations, suggest that heterologous components seen in some myxoid liposarcomas reflect a metaplastic phenomenon and not a real dedifferentiation phenomenon, challenging the concept of "dedifferentiated" myxoid liposarcoma.

Myxoid liposarcoma with cartilaginous differentiation: A case study with fish analysis and review of the literature

Cartilaginous differentiation is rarely encountered in myxoid liposarcomas. To date, a small number of such cases have been described, and molecular or cytogenetic analysis was performed only in few of them. In the present study, we describe a primary myxoid liposarcoma with cartilaginous differentiation which arised in the left thigh of a 37-year-old man. Miscroscopically, the tumor consisted of areas with typical myxoid liposarcoma morphology and areas of sharply demarcated hyaline cartilage nodules. Here, we present the results of Fluorescence In Situ Hybridization (FISH) analysis that revealed the presence of FUS and DDIT3 gene rearrangements in both the liposarcomatous and cartilaginous components of the tumor. These findings confirm the neoplastic nature of the cartilage component in this rare tumor.

Myxoid liposarcoma with cartilaginous differentiation: a case study with cytogenetical analysis

Myxoid liposarcoma is a subtype of liposarcoma. This specific subtype can be identified based on its characteristic histological and cytogenetical features. The tumor has a fusion transcript of the CHOP and TLS genes, which is caused by t(12;16)(q13;p11). Most of the fusion transcripts that have been identified fall into three categories, specifically type I (exons 7-2), type II (exons 5-2), and type III (exons 8-2). A total of seven myxoid liposarcomas associated with the rare phenomenon of cartilaginous differentiation have been documented in the literature. Currently, only one of these cases has been cytogenetically analyzed, and the analysis indicated that it was a type II TLS-CHOP fusion transcript in both the typical myxoid liposarcoma and cartilaginous areas. This study presents a second report of myxoid liposarcoma with cartilaginous differentiation, and includes a cytogenetical analysis of both the myxoid and cartilaginous areas.

The expanded histologic spectrum of myxoid liposarcoma with an emphasis on newly described patterns: implications for diagnosis on small biopsy specimens

The variety of histologic patterns in myxoid liposarcoma is underappreciated. The diversity of these patterns can lead to diagnostic difficulty. We examined the morphologic spectrum of myxoid liposarcoma by cataloguing and describing different patterns identified in biopsy and resection specimens of 46 primary, recurrent, and metastatic myxoid liposarcomas. The patterns identified in the 46 cases included traditional myxoid (43 [93%]), traditional round cell (17 [37%]), pseudoacinar (24 [52%]), lipoblast-rich (13 [28%]), island (11 [24%]), lipomatous (10 [22%]), stromal hyalinization (7 [15%]), cord-like (5 [11%]), nested (3 [7%]), chondroid metaplasia (2 [4%]), and hemangiopericytoma (HPC)-like (1 [2%]). Island and nested patterns had not previously been described. The diagnosis of myxoid liposarcoma was confirmed by fluorescence in situ hybridization studies for DDIT3 (also known as CHOP) rearrangement. The morphologic spectrum of myxoid liposarcoma spans well beyond its typical appearance of spindle cells in a myxoid stroma with a prominent vascular pattern. Awareness of the variety of histologic patterns is critical to avoid misdiagnosis, especially in small biopsy specimens.

TGF-beta inhibitors for the treatment of cancer

Advances in understanding the role of transforming growth factor (TGF)-beta in tumorigenesis have led to the development of TGF-beta inhibitors for cancer treatment. Three platforms of TGF-beta inhibitors have evolved: antisense oligonucleotides, monoclonal antibodies and small molecules. In this review, the current stage of development of each known TGF-beta inhibitor will be discussed. As part of the risk/benefit assessment of TGF-beta inhibitors, the known effects of TGF-beta deficiency in mice, non-clinical toxicology studies with TGF-beta inhibitors in rats, and the clinical studies with monoclonal antibodies against TGF-beta will be summarised.

Divergent differentiation in malignant soft tissue neoplasms: the paradigm of liposarcoma and malignant peripheral nerve sheath tumor

In tumors clonality does not always translate into morphologic uniformity. While most sarcomas exhibit only one line of histologic differentiation, a minority may display a strikingly diverse phenotype in addition to the main lineage. This phenomenon not only presents a diagnostic problem but also raises questions about the commitment of tumor cells toward a specific phenotype. Among sarcomas, malignant peripheral nerve sheath tumor (MPNST) and dedifferentiated liposarcoma are two entities in which divergent differentiation is a relatively frequent event. Diagnostically it is crucial to recognize the "primary" sarcoma in such tumors correctly and distinguish it from the "secondary" divergent elements. The presence of the latter could be the first morphologic clue to a specific sarcoma type. Even though it may be difficult to explain the pathogenesis of divergent differentiation, divergence still illustrates that the phenotype of a tumor cell is not set in stone but can be modulated or switched by a number of factors.