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Myxoid and round-cell liposarcomas share the translocation t(12;16)(q13;p11) creating the TLS-CHOP fusion gene as a common genetic alteration. We previously reported several unique characteristics of genomic sequences around the breakpoints in the TLS and CHOP loci, and among them was the presence of consensus recognition motifs of Translin, a protein that associates with chromosomal translocations of lymphoid neoplasms. We further extended our search for Translin binding motifs in sequences adjacent to breakpoints and investigated whether Translin binds to these sequences in vitro by mobility-shift assay. Computer-assisted search found sequences highly homologous (>70%) with Translin binding motifs adjacent to the breakpoints in 10 out of 11 liposarcomas with the TLS-CHOP fusion genes. All of 13 oligonucleotides corresponding to the putative binding sequences in these cases bind to Hela cell extract and also recombinant Translin protein, although the binding affinity of each motif showed considerable differences. The DNA-protein complex formation was inhibited by non-labeled competitor or anti-Translin antibody, suggesting the specificity of the complex formation. Considering the high incidence and specific binding property, the presence of Translin binding motif may be one of the important determinants for the location of breakpoints in the TLS and CHOP genes in liposarcomas.

Discal cysts—intraspinal cysts communicating with an adjacent intervertebral disc—are an uncommon cause of lumbar radiculopathy. We report a case of discal cyst of the lumbar spine. The cyst contents were bloody and clotted rapidly; no disc materials were seen. Communication between the cyst and the intervertebral disc was detected. Histopathology of the cyst wall revealed fibrous connective tissue without synovial lining cells. We hypothesise that the discal cyst was formed by haemorrhage of the epidural venous plexus caused by separation of the peridural membrane by mechanical force transmitted by an annulus fibrosis fissure. The minute segmental motion caused by the affected disc may have stimulated continuous bleeding.

Fusion of TLS/FUS and CHOP gene by reciprocal translocation t(12;16)(q32;q16) is a common genetic event found in myxoid and round-cell liposarcomas. Characterization of this genetic event was performed by three methods, Southern blot, RT-PCR, and genomic long-distance PCR in nine myxoid and three round-cell liposarcomas. All but one tumors showed genetic alternations indicating the fusion of TLS/FUS and CHOP gene. Two novel types of fusion transcripts were found, of which one lacked exon 2 sequence of CHOP gene, and the other lacked 3' half of exon 5 of TLS gene. The latter case was caused by a cryptic splicing site which was created by the genomic fusion. Detailed analyses genomic fusion points revealed several sequence characteristics surrounding the fusion points. Homology analyses of breakpoint sequences with known sequence motifs possibly involve in the process of translocation uncovered Translin binding sequences at both of TLS/ FUS and CHOP breakpoints in two cases. Translocations were always associated with other genetic alterations, such as deletions, duplications, or insertions. Short direct repeats were almost always found at both ends of deleted or duplicated fragments some of which had apparently been created by joining of sequences that flank the rearrangement. Finally, consensus topoisomerase II cleavage sites were found at breakpoints in all cases analysed, suggesting a role of this enzyme in creating staggered ends at the breakpoint. These data suggested that sequence characteristics may play an important role to recruit several factors such as Translin and topoisomerase II in the process of chromosomal translation in liposarcomas.

We have studied 107 bone and soft-tissue sarcomas and 8 lipomas for amplification of the MDM2 gene. This gene was amplified in 3 out of 67 osteosarcomas, 3 out of 20 malignant fibrous histiocytomas, 4 out of 20 liposarcomas, and 4 out of 8 lipomas. The amplification was associated with overexpression of mRNA. In osteosarcomas, contrary to previous findings, all amplifications were observed in primary lesions. In liposarcomas, the amplification was seen exclusively in well-differentiated tumors with high frequency (4/5) but not in other subtypes (0/15). In addition, MDM2 amplification was also frequently found in deep-seated intra- or intermuscular lipomas (4/5). Hence, it is suggested that MDM2 amplification plays a significant role in the development of differentiated adipose-tissue tumors. Three well-differentiated liposarcomas with MDM2 amplification coexisted with high-grade dedifferentiated sarcomas, in which MDM2 amplification was also observed. Interestingly, in 2 of these cases, the grades of amplification correlated with the histological grades, indicating an important role of MDM2 overexpression in tumor progression.

Background Periprosthetic femoral fractures are becoming increasingly common and are a major complication of total hip arthroplasty and hemiarthroplasty. The treatment of periprosthetic femoral fracture after femoral revision using a long stem is more complex and challenging. The purpose of this study was to identify the clinical and radiographical features of periprosthetic femoral fractures after revision using a long stem. Methods We report a retrospective review of the outcomes of treatment of 11 periprosthetic fractures after femoral revision using a long stem. Eleven female patients with a mean age of 79.2 years (70 to 91) were treated for a Vancouver type B1 fracture between 1998 and 2013. The mean numbers of previous surgeries were 3.1 (2 to 5). Results The average follow-up was 58.9 months (8 to 180). We found several important features that might influence the outcome of treatment for periprosthetic femoral fractures after femoral revision using a long stem: 1) all cases were classified as Vancouver type B1. 2) 6 patients (55%) had a transverse fracture around the tip of the long stem. 3) 7 patients (64%) had a history of previous fracture of the ipsilateral femur. The type B1 fractures were treated with open reduction and internal fixation in 9 hips, 6 of which were reinforced with bone grafts. Two other periprosthetic fractures were treated with femoral revision. One was revised because of stem breakage, and the other was a transverse fracture associated with poor bone quality, which received a femoral revision with a long stem and a plate. All fractures except one achieved primary union. This failed case had a bone defect at the fracture site, and revision surgery using a cementless long stem and allografts was successful. Conclusions These findings suggest that most cases of type B1 fracture after revision using a long stem have been treated successfully with open reduction and internal fixation. However, a transverse fracture with very poor bone quality might be considered as a type B3 fracture, and femoral revision might be a treatment of choice.

Background Several authors reported encouraging results of total hip arthroplasty (THA) for Crowe IV hips performed using shortening osteotomy. However, few papers have documanted the results of THA for Crowe IV hips without shortening osteotomy. The aim of the present study was to assess the long term-results of cemented THAs for Crowe group IV hips performed without subtrochanteric shortening osteotomy. Methods We have assessed the long term results of 27 cemented total hip arthroplasty (THA) performed without subtrochanteric osteotomy for Crowe group IV hip. All THAs were performed via transtrochanteric approach. Results After a mean follow-up of 10.6 (6 to 17.9) years, 25 hips (92.6%) had survived without revision surgery and survivorship analysis gave a survival rate of 96.3% at 10 years with any revision surgery as the end point. Although mean limb lengthening was 3.2 (1.0 to 5.1) cm, no hips developed nerve palsy. Complications occurred in four hips, necessitating revision surgery in two. Among the four complications, three involved the greater trochanter, two of which occurred in cases where braided cables had been used to reattach the greater trochanter. Conclusions Although we encountered four complications, including three trochanteric problems, our findings suggest that THA without subtrochanteric shortening osteotomy can provide satisfactory long-term results in patients with Crowe IV hip.