The impact of human immune deficiency virus and hepatitis C coinfection on white matter microstructural integrity.

The purpose of the present study is to examine the integrity of white matter microstructure among individuals coinfected with HIV and HCV using diffusion tensor imaging (DTI). Twenty-five HIV+ patients, 21 HIV+/HCV+ patients, and 25 HIV- controls were included in this study. All HIV+ individuals were stable on combination antiretroviral therapy (cART; ≥3 months). All participants completed MRI and neuropsychological measures. Clinical variables including liver function, HIV-viral load, and CD4 count were collected from the patient groups. DTI metrics including mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), and fractional anisotropy (FA) from five subregions of the corpus callosum were compared across groups. The HIV+/HCV+ group and HIV+ group were similar in terms of HIV clinical variables. None of the participants met criteria for cirrhosis or fibrosis. Within the anterior corpus callosum, significant differences were observed between both HIV+ groups compared to HIV- controls on DTI measures. HIV+ and HIV+/HCV+ groups had significantly lower FA values and higher MD and RD values compared to HIV- controls; however, no differences were present between the HIV+ and HIV+/HCV+ groups. Duration of HIV infection was significantly related to DTI metrics in total corpus callosum FA only, but not other markers of HIV disease burden or neurocognitive function. Both HIV+ and HIV+/HCV+ individuals had significant alterations in white matter integrity within the corpus callosum; however, there was no evidence for an additive effect of HCV coinfection. The association between DTI metrics and duration of HIV infection suggests that HIV may continue to negatively impact white matter integrity even in well-controlled disease.

Alterations of INK4A and INK4B genes in adult soft tissue sarcomas: effect on survival.

BACKGROUND: The INK4A and INK4B genes map to chromosome 9p21, with the INK4A gene encoding two protein products, p16 and pl9ARF. Alterations of the INK4A and INK4B genes occur frequently in certain primary malignant neoplasms. This study was undertaken to evaluate the frequency of INK4A and INK4B gene alterations in a cohort of adult soft tissue sarcomas. METHODS: The status of the INK4A and INK4B genes was determined in 46 soft tissue sarcomas by use of the following methods: Southern blotting, polymerase chain reaction (PCR), single-strand conformation polymorphism analysis, comparative multiplex PCR, and a methylation assay focusing on the p16 promoter. Associations between alterations of the INK4A and INK4B genes and clinicopathologic variables, as well as with p53 and pRB (retinoblastoma protein) status, were evaluated by use of the two-tailed Fisher's exact test. Disease-specific survival was evaluated by use of the Kaplan-Meier method and the logrank test. Proportional hazards analysis was used to obtain estimates of relative risks. All P values are two-sided. RESULTS: Homozygous and hemizygous deletions, but no point mutations, were observed in these two genes. The overall frequency of gene alteration (deletion or rearrangement) was approximately 15% for the INK4A and INK4B genes, with changes restricted to high-grade sarcomas. Statistically significant associations were observed between INK4A/INK4B deletions (P = .036) or alterations (P = .005) and poor survival. Alteration of the INK4A and INK4B genes was the only statistically significant predictor for poor survival when controlling for tumor grade and size (P = .03). CONCLUSION/IMPLICATIONS: Coincident homozygous deletion of the INK4A and INK4B genes occurs frequently in adult soft tissue sarcomas. Loss of p16 and pl9ARF function in primary tumors, although not equivalent to alterations in p53 and pRB function, appears to be associated with cancers that have an aggressive biologic behavior.

Prognostic implications of p53 nuclear overexpression and high proliferation index of Ki-67 in adult soft-tissue sarcomas.

BACKGROUND: Morphologically similar soft-tissue sarcomas may behave in very different fashions, making it difficult to predict clinical outcomes and to properly design therapeutic interventions. In a preliminary study, we observed that TP53 mutations and nuclear overexpression of p53 protein were frequent events in soft-tissue sarcoma, and we noticed an association between p53-positive phenotype and poor clinical outcome. PURPOSE: We examined the potential clinical relevance of p53 overexpression in adults with soft-tissue sarcomas. We also studied the clinical implications of a high proliferation index. METHODS: A cohort of 174 adults with soft-tissue sarcomas were analyzed using anti-p53 and anti-Ki-67 antibodies and immunohistochemical assays on consecutive fresh frozen tissue samples. RESULTS: We observed a significant association between p53 nuclear overexpression and tumor grade (P = .001) and tumor size (P = .01). Patients displaying a p53-positive phenotype had significantly reduced survival (P = .02). Similarly, a significant difference was observed between high proliferation index and tumor grade (P < .001) and reduced patient survival (P = .03). A high Ki-67 proliferation index was detected in association with p53 nuclear overexpression. CONCLUSIONS: Overexpression of p53 protein and a high proliferation index strongly correlate with poor clinical outcome and reduced survival in patients having soft-tissue sarcomas.

Characterization of molecular abnormalities in human fibroblastic neoplasms: a model for genotype-phenotype association in soft tissue tumors.

Desmoid tumors and fibrosarcomas (FS) are part of a wide spectrum of disordered fibroblastic growth that display striking clinical and phenotypic differences. This study was designed to characterize molecular abnormalities that are associated with these differences and to determine their clinical relevance. A cohort of 24 desmoid tumors and 25 low-grade (LG) and 14 high-grade (HG) FS that were clinically and pathologically well characterized was analyzed for alterations in expression of Ki-67, Bcl-2, retinoblastoma gene product (pRB), and p53 by immunohistochemistry. LG-FS and HG-FS showed abnormal expression of Ki-67 (32 versus 86%), Bcl-2 (48 versus 57%), and pRB (56 versus 93%). In contrast, desmoid tumors showed a normal phenotype with these markers. p53 overexpression was identified in 20% of LG-FS and in 29% of HG-FS cases but only in 4% of desmoid tumors. There was an increasing trend in the proportion of abnormal expression of Ki-67, Bcl-2, pRB, and p53 with the increase of tumor aggressiveness from desmoid tumors to LG-FS to HG-FS. The molecular differences between tumor entities were highly statistically significant (P < 0.01). Significant associations between abnormal expression of pRB and recurrence-free survival of LG-FS patients (P = 0.05) and between Ki-67 overexpression and recurrence-free survival for tumors of >5 cm were observed (P = 0.02). The demonstrated differences of molecular alterations in HG-FS, LG-FS, and desmoids appear to be related to biological aggressiveness of such tumors, and they might be useful to differentiate between histologically similar cases of desmoid tumors and LG-FS. pRB and Ki-67 status may be useful to predict recurrence in certain subsets of patients.

Molecular abnormalities of mdm2 and p53 genes in adult soft tissue sarcomas.

Genetic alterations in the p53 and mdm2 genes have been reported to occur in soft tissue sarcomas. This study was designed to determine the prevalence and potential clinical value of detected molecular abnormalities and altered patterns of expression of mdm2 and p53 genes in adult soft tissue sarcomas. A cohort of 211 soft tissue sarcomas from adults that were both clinically and pathologically well characterized was analyzed. Monoclonal antibodies directed against mdm2 and p53 proteins were used to measure overexpression of these proteins in the nuclei of cells from sections of these tumors. Seventy-six of 207 tumors had abnormally high levels of mdm2 proteins and 56 of 211 tumors overexpressed p53 protein. Twenty-two cases had abnormally high levels of both mdm2 and p53 proteins based upon immunoreactivity with these antibodies. There was a striking statistically significant correlation between the overexpression of p53 and mdm2 proteins in the same tumor and poor survival (P < 0.05) of the patients. A group of 73 soft tissue sarcomas was chosen for analysis using Southern blots, single strand conformation polymorphisms, and direct DNA sequencing to confirm mdm2 gene amplifications and p53 mutations and correlate these with the results of the immunoreactivities. The overexpression of p53 and mdm2 proteins in the nuclei of tumor cells did not always correlate well with gene amplification at the mdm2 locus or mutation at the p53 gene. The possible reasons for these discrepancies are discussed.

A prospective randomized trial of adjuvant brachytherapy in the management of low-grade soft tissue sarcomas of the extremity and superficial trunk.

PURPOSE: This study was designed to evaluate the impact of adjuvant brachytherapy (BRT) on local and systemic recurrence rates in patients with low-grade sarcoma. PATIENTS AND METHODS: Forty-five patients with histologic low-grade, completely resected soft tissue sarcomas of the extremity or superficial trunk were entered onto this trial. Following resection of all gross disease, patients were randomized to the BRT arm (n = 22) or to the no-BRT arm (n = 23). On the fifth or sixth postoperative day, catheters were loaded with iridium 192 to deliver a dose of 45 Gy to the tumor bed over 4 to 6 days. RESULTS: The two groups were evenly distributed with respect to the distribution of presentation status (primary v recurrent), tumor site (trunk v extremity, proximal v distal extremity), tumor size (< 5 cm v > or = 5 cm), tumor depth (superficial v deep), and microscopic tumor margins (positive v negative). The predominant histopathologic diagnosis in each group was liposarcoma (BRT, 13 of 22 [59%]; no BRT, 14 of 23 [61%]) with other histopathologic subtypes evenly distributed between the two groups. The median follow-up duration among the ongoing survivors is 67 months. One patient in the BRT group developed systemic disease and died of progressive disease. Local recurrence occurred in five of 23 patients (22%) in the no-BRT group and six of 22 patients (27%) in the BRT group (P = .60). CONCLUSION: Adjuvant radiation in the form of BRT does not appear to decrease local recurrence rates following complete resection of low-grade extremity and superficial trunk soft tissue sarcomas. Other adjuvant approaches, such as external-beam radiotherapy, are required to have a significant impact on local recurrence rates in this group of patients.

Association of local recurrence with subsequent survival in extremity soft tissue sarcoma.

PURPOSE: The aim of this study was to analyze local recurrence in a large cohort of prospectively followed patients with primary extremity soft tissue sarcoma. In particular, we analyzed the correlation of local recurrence with subsequent metastasis and disease-specific survival. PATIENTS AND METHODS: Patients who underwent treatment for primary extremity soft tissue sarcoma from July 1982 through July 1995 at Memorial Sloan-Kettering Cancer Center were the subject of this study. Local recurrence, distant metastasis, and disease-specific survival were used as end points of the study. The influence of local recurrence on subsequent distant metastasis and disease-specific survival were examined using the Cox proportional hazards model. RESULTS: We treated 911 patients, of whom 297 (33%) developed recurrent disease. Local recurrence occurred in 116 patients (13%), metastasis in 167 (18%), and synchronous local recurrence and metastasis in 13 (2%). Of 116 patients who developed local recurrence, 38 subsequently developed metastasis and 34 died of disease. Metastasis after local recurrence was predicted in patients with initial high-grade (P = .005; risk = 3.5) or deep (P = .02; risk = 2.9) tumors. Tumor mortality after local recurrence was predicted in patients with initial high-grade (P = .007; risk = 3.7) or large (> 5 cm; P = .01; risk = 3.2) primary tumors. DISCUSSION: These findings suggest that there is a strong association of local recurrence with the development of subsequent metastasis and tumor mortality, and that local recurrence is a poor prognostic factor. It would seem prudent to consider patients who develop local recurrence and have high-grade tumors as being at high risk for systemic disease and therefore eligible for investigational adjuvant systemic therapy.

Long-term results of a prospective randomized trial of adjuvant brachytherapy in soft tissue sarcoma.

PURPOSE: This trial was performed to evaluate the impact of adjuvant brachytherapy on local and systemic recurrence rates in patients with soft tissue sarcoma. PATIENTS AND METHODS: In a single-institution prospective randomized trial, 164 patients were randomized intraoperatively to receive either adjuvant brachytherapy (BRT) or no further therapy (no BRT) after complete resection of soft tissue sarcomas of the extremity or superficial trunk. The adjuvant radiation was administered by iridium-192 implant, which delivered 42 to 45 Gy over 4 to 6 days. The two study groups had comparable distributions of patient and tumor factors, including age, sex, tumor site, tumor size, and histologic type and grade. RESULTS: With a median follow-up time of 76 months, the 5-year actuarial local control rates were 82% and 69% in the BRT and no BRT groups (P = .04), respectively. Patients with high-grade lesions had local control rates of 89% (BRT) and 66% (no BRT) (P = .0025). BRT had no impact on local control in patients with low-grade lesions (P = .49). The 5-year freedom-from-distant-recurrence rates were 83% and 76% in the BRT and no BRT groups (P = .60), respectively. Analysis by histologic grade did not demonstrate an impact of BRT on the development of distant metastasis, despite the improvement in local control noted in patients with high-grade lesions. The 5-year disease-specific survival rates for the BRT and no BRT groups were 84% and 81% (P = .65), respectively, with no impact of BRT regardless of tumor grade. CONCLUSION: Adjuvant brachytherapy improves local control after complete resection of soft tissue sarcomas. This improvement in local control is limited to patients with high-grade histopathology. The reduction in local recurrence in patients with high-grade lesions is not associated with a significant reduction in distant metastasis or improvement in disease-specific survival.

Synovial sarcoma: a multivariate analysis of prognostic factors in 112 patients with primary localized tumors of the extremity.

PURPOSE: Synovial sarcoma is a high-grade tumor that is associated with poor prognosis. Previous studies analyzing prognostic factors are limited because of inclusion of heterogeneous cohorts of patients with nonextremity and recurrent tumors. The objective of this study was to determine independent prognostic factors of primary synovial sarcoma localized to the extremity. PATIENTS AND METHODS: Between July 1, 1982, and June 30, 1996, 112 patients underwent surgical resection for cure at our institution and then were followed-up prospectively. Clinical and pathologic factors examined for prognostic value included age, sex, tumor site and location, depth, size, microscopic status of surgical margins, invasion of bone or neurovascular structures, and monophasic or biphasic histology. The end points analyzed were the time to first local recurrence that was not preceded by a distant recurrence, time to any distant recurrence, and time to disease-related mortality. These end points were modeled using the method of Kaplan and Meier and analyzed by the log-rank test and Cox regression. RESULTS: The median duration of follow-up among survivors in this cohort of 112 patients was 72 months. The 5-year local-recurrence, distant-recurrence, and mortality rates were 12%, 39%, and 25%, respectively. Tumor size > or = 5 cm (P =.001; relative risk [RR] = 2. 7; 95% confidence interval [CI], 1.5 to 5.2) and the presence of bone or neurovascular invasion (P =.04; RR = 2.3; 95% CI, 1.0 to 5. 3) were independent adverse predictors of distant recurrence. Tumor size > or= 5 cm (P =.003; RR = 2.3; 95% CI, 1.4 to 6.3) and the presence of bone or neurovascular invasion (P =.03; RR = 2.7; 95% CI, 1.0 to 6.5) were also independent adverse predictors of mortality. CONCLUSION: The natural history of primary synovial sarcoma of the extremity is related to tumor size and invasion of bone and neurovascular structures.

Prognostic factors associated with long-term survival for retroperitoneal sarcoma: implications for management.

PURPOSE: Retroperitoneal soft tissue sarcomas are rare tumors. Studies characterizing long-term follow-up and patterns of recurrence are limited. The purpose of this analysis is to identify patterns of recurrence and prognostic factors associated with long-term survival after resection of retroperitoneal soft tissue sarcomas. METHODS: Between July 1, 1982, and June 30, 1990, 198 adult patients were identified from our prospective soft tissue sarcoma database carrying the diagnosis of retroperitoneal soft tissue sarcoma who were eligible for > or = 5 years of follow-up. Of these, 48 patients (25%) were documented to be alive > or = 5 years from the time of operation. Statistical analysis was by log-rank or Wilcoxon test for univariate analysis. Multivariate analysis was by the Cox model. RESULTS: The recurrence rate during the follow-up period was approximately 5% per year from the time of initial operation. Of the patients who were disease-free for > or = 5 years from initial surgery, 40% recurred by 10 years. Radiation therapy was the only factor significant (P = .02) for a reduction in the risk of local recurrence. Age < or = 50 years and high-grade tumors were significant factors (P = .003 and .009, respectively) for an increased risk of distant metastasis. Incomplete gross resection was the only factor significant for an increased risk of tumor mortality (P = .003). CONCLUSION: Complete surgical resection at the time of primary presentation is likely to afford the best chance for long-term survival. With long-term follow-up, it is clear that recurrence will continue to occur, and a 5-year disease-free interval is not a cure. Patients with an incomplete initial resection, age less than 50 years, and high-grade tumors are candidates for investigational adjuvant therapy.

Monoclonality of multifocal myxoid liposarcoma: confirmation by analysis of TLS-CHOP or EWS-CHOP rearrangements.

Multifocal presentation, defined as the presence of tumor at two or more anatomically separate sites, before the manifestation of disease in sites where sarcomas usually metastasize (e.g., lungs) occurs in about 1% of extremity soft tissue sarcomas (STSs). Debate still persists whether multifocal STSs represent an unusual pattern of metastasis or multiple separate primary tumors. Among STSs with multifocal presentation, myxoid liposarcoma is the predominant histological type. This subtype of liposarcoma contains the specific t(12;16) chromosomal translocation, which results in rearrangement of the TLS and CHOP genes that is clone specific at the DNA level. We, therefore, sought to address the question of clonality by molecular analysis in six patients who presented with either synchronous or metachronous multifocal myxoid liposarcoma. In all six cases, adequate frozen tumor was available for DNA extraction from at least two distinct anatomical sites. Southern blot analysis using CHOP, TLS, and EWS cDNA probes was performed on genomic DNA. Five cases contained a TLS-CHOP rearrangement, and one case had the variant EWS-CHOP fusion (seen in <5% of cases). The size of the rearranged CHOP fragment differed among the six patients, as expected, but was identical in all anatomically separate tumor samples from each patient. Likewise, the sizes of the rearranged bands observed with either the TLS or EWS probes supported the monoclonality of all cases. Our results confirm the monoclonal origin of multifocal myxoid liposarcoma, establishing the metastatic nature of distant soft tissue lesions in these cases. It remains unclear whether this unusual pattern of metastasis represents an intrinsic property of this subset of myxoid liposarcoma or merely a rare chance occurrence. The clinical outcomes observed in this small series suggest that the prognosis of multifocal myxoid liposarcoma is poor, regardless of its often bland or "low-grade" histological appearance.

Overexpression of cyclin D1 is associated with poor prognosis in extremity soft-tissue sarcomas.

Binding of G1 cyclins to cyclin-dependent kinases leads to phosphorylation of the retinoblastoma protein and progression through G1 and S phases of the cell cycle. Overexpression of cyclins is thought to deregulate this process and has been noted in many human malignancies. This study was conducted to assess patterns of expression and potential gene amplification of the G1 cyclins in 84 patients affected with extremity soft-tissue sarcomas. Sixty cases were primary tumors, whereas the remaining 24 cases were locally recurrent lesions. There were 58 high-grade and 26 low-grade tumors. Immunohistochemical analyses were conducted using antibodies to cyclins D1, E, and A. Southern blot analysis was performed on DNA available from 53 of 84 patients with a cyclin D1-specific probe. Cyclin D1 overexpression was noted in 23 of 79 informative cases (29%), whereas cyclin E was found overexpressed in 26 of 80 cases (33%) and cyclin A overexpression was observed in 9 of 81 cases (11%). Overexpression of cyclins D1, E, or A each correlated significantly with high tumor grade (P <0.05). On multivariate analysis, neither cyclin E nor cyclin A were significant predictors of outcome. However, overexpression of cyclin D1 was significantly associated with worse overall survival for the entire group as well as in the subset of high-grade lesions (P <0.05), notwithstanding the relatively short follow-up time (mean, 2.4 years). Nevertheless, the presence of a significant association between laboratory data and outcome implies that the study is adequately powered. Furthermore, none of the cases demonstrated CCND1 gene amplification. These data support the concept that cyclin D1 overexpression determines the evolution of a particularly aggressive subset of these lesions.

Prognostic impact of P53 status, TLS-CHOP fusion transcript structure, and histological grade in myxoid liposarcoma: a molecular and clinicopathologic study of 82 cases.

PURPOSE: A specific TLS-CHOP fusion gene resulting from the t(12;16) is present in at least 95% of myxoid liposarcomas (MLS). Three common forms of the TLS-CHOP fusion have been described, differing by the presence or absence of TLS exons 6-8 in the fusion product. Type 5-2 (also known as type II) consists of TLS exons 1-5 fused to CHOP exon 2; type 7-2 (also known as type I) also includes TLS exons 6 and 7 in the fusion, whereas type 8-2 (also known as type III) fuses TLS exons 1-8 to CHOP exon 2. We sought to determine the impact of TLS-CHOP fusion transcript structure on clinical outcome in a group of well-characterized MLS cases. We also analyzed P53 status, because this parameter has been found to have a significant prognostic impact in other sarcomas with chromosomal translocations. METHODS: We analyzed TLS-CHOP fusion transcripts by reverse-transcription PCR using RNA extracted from frozen tissue in 82 MLS confirmed previously to harbor a CHOP rearrangement either by Southern blotting or by cytogenetic detection of the t(12;16). Parameters analyzed included age, location, size, percentage of round cell (RC) component, areas of increased cellularity, necrosis, and surgical margins. In 71 (87%) cases, adequate tumor tissue was available for immunohistochemical analysis of P53 status, using DO7 antibody. The Kaplan-Meier method, log-rank, and Cox regression tests were used for survival analyses. RESULTS: Most MLS were >10 cm (73%), arising in the thigh (70%), and localized at presentation (89%). RC component was <5% in 47 (57%) cases and > or =5% in 35 (43%). The TLS-CHOP fusion transcript was type 5-2 in 55 (67%), type 7-2 in 16 cases (20%), and type 8-2 in 8 (10%). One tumor had a unique variant fusion, between exon 6 TLS and exon 2 CHOP. Two other cases (2%) showed an EWS-CHOP fusion transcript. Overexpression of P53 (defined as > or =10% nuclear staining) was detected in 12 (17%) cases. High histological grade (defined as > or =5% RC; P < 0.01), presence of necrosis (> or =5% of tumor mass; P < 0.05), and overexpression of P53 (P < 0.001) correlated with reduced metastatic disease-free survival in localized tumors. The presence of negative surgical margins (P < 0.01) and extremity location (P = 0.02) were found to be significant in predicting local recurrence in the entire group as well as localized cases by univariate and multivariate analysis. Although there was no significant correlation between TLS-CHOP transcript type and histological grade or disease-specific survival, an association was found between the P53 status and type 5-2 fusion (P < 0.01). CONCLUSION: In contrast to some other translocation-associated sarcomas, the molecular variability of TLS-CHOP fusion transcript structure does not appear to have a significant impact on clinical outcome in MLS. Instead, high histological grade (> or =5% RC), presence of necrosis, and P53 overexpression are predictors of unfavorable outcome in localized MLS.

Adjuvant radiotherapy for margin-positive high-grade soft tissue sarcoma of the extremity.

PURPOSE: Adjuvant radiotherapy (RT) has been shown to improve local control in patients with soft tissue sarcoma of the extremities (STS). The specific impact of adjuvant radiation on patients with positive margins, however, has not been clearly defined. The purpose of this study was to determine if adjuvant RT improves local control in patients with high-grade STS who had positive margins of resection. METHODS AND MATERIALS: Between 8/82 and 2/97, 110 adult patients with primary high-grade STS of an extremity underwent limb sparing surgery and were found to have a histologically positive microscopic surgical margin. Ninety-one (83%) received RT and 19 (17%) had no RT. The two groups were balanced with regard to size, site, location, and tumor depth. Adjuvant RT was delivered with brachytherapy (BRT) alone in 34 patients, external beam radiotherapy (EBRT) alone in 33 patients, or BRT+EBRT in 24 patients. The BRT dose was 45 Gy when used alone and 15-20 Gy when used as a boost. The EBRT dose was 60-70 Gy when used alone and 45-50 Gy when given with BRT. The median follow-up time was 41 months (range, 3-186 months). RESULTS: The overall 5 year local control rate was 71%. This rate was significantly higher in the RT group compared to the no RT group (74% vs. 56%, respectively) (p = 0.01). On univariate analysis, lower extremity site and proximal location were also found to be predictors of improved local control (p = 0.03 and 0.03, respectively). However, only proximal location and the use of RT retained their significance as predictors of improved local control on multivariate analysis (p = 0.003 and 0.01, respectively). The overall 5-year distant relapse-free survival, disease-free survival, and overall survival rates were 54%, 44%, and 53%, respectively. No statistical differences were found in these survival rates between RT and no RT groups. CONCLUSION: Based on this study, adjuvant radiotherapy seems to improve local control in patients with high-grade STS of the extremity with positive margins. However, local recurrence still occurs in a substantial proportion of patients, mandating further need for improvement.

Specificity of TLS-CHOP rearrangement for classic myxoid/round cell liposarcoma: absence in predominantly myxoid well-differentiated liposarcomas.

Myxoid liposarcoma (LS), the most common subtype of LS, is known to be characterized by the specific t(12;16) resulting in a TLS-CHOP fusion in almost all cases. We wished to address the following questions: (i) Is this genetic hallmark also present in other types of LS with predominant myxoid change? (ii) What is the proportion of cases with the variant EWS-CHOP fusion? (iii) What is the optimal approach for Southern blot detection of TLS breakpoints? We identified 59 LS characterized histologically by >90% myxoid component, in which frozen tissue tumor was available for DNA extraction. These 59 LS with myxoid features were divided into 2 groups: 42 LS with classic myxoid/round cell appearance (myxoid LS) and 17 well-differentiated LS (WDLS) with a predominant (>90%) myxoid component. Within the myxoid LS group, 29 tumors were low grade and 13 high grade (>20% round cell component). Among the 17 predominantly myxoid WDLS, there were 15 low grade and 2 focally high grade tumors. In addition, we selected as control group, 20 LS of other histological types with minimal or no myxoid change (17 WDLS and 3 pleomorphic LS) and 13 myxofibrosarcomas. Southern blot analysis was performed in all cases using a CHOP cDNA probe, and in all CHOP rearranged cases using a TLS cDNA probe. Probe/enzyme combinations for Southern blot analysis were CHOP exon 3-4 cDNA probe with BamHI or SacI, TLS exon 3-6 cDNA probe with BclI. All 42 cases of myxoid LS showed a CHOP rearrangement and 38 of them also had a TLS rearrangement. Among the 4 myxoid LS without Southern blot evidence of TLS rearrangement, 1 showed an EWS-CHOP fusion by Southern blotting and reverse transcriptase-polymerase chain reaction and in another case, reverse transcriptase-polymerase chain reaction detected a TLS-CHOP fusion transcript. None of the predominantly myxoid WDLS and none of the tumors included in the control group showed rearranegements with CHOP probe. In addition, 12 predominantly myxoid WDLS, 10 other LS, and 5 myxofibrosarcoma from the control group were also tested for TLS rearrangement; all were negative. The TLS-CHOP fusion is highly sensitive and specific for the entity of classic myxoid/round cell LS. Other types of LS, even with a predominant myxoid component, lack the TLS-CHOP rearrangement, confirming that they represent a genetically distinct group of LS. The prevalence of the EWS-CHOP variant fusion was approximately 2% in this series. The optimal enzyme for TLS genomic breakpoint detection is BclI.

Schwannoma (neurilemoma) with malignant transformation. A rare, distinctive peripheral nerve tumor.

Malignant transformation of a schwannoma (neurilemoma) is an exceedingly rare event. We describe two cases with such change and review the reported purported examples. The tumors in our patients involved a finger and pelvis. Sex, age, and clinical follow-up were available for only the second case, involving a 31-year-old man who died with recurrent and metastatic tumor. Seven acceptable cases were found in the literature. Analysis of the nine cases of schwannoma with malignant transformation showed no sex predilection, but revealed a tumor differing significantly from conventional malignant peripheral nerve sheath tumors. The mean age (56 years) was two decades older, no patient had neurofibromatosis, in four cases there was a years-long history of an antecedent mass, and in none of the cases was the malignant component an interlacing, fasciculated spindle-cell tumor. Rather, the malignant component was commonly purely epithelioid (seven of nine cases). In the two other cases, cells of the malignant component had neuroepithelial features. The prognosis for patients with schwannomas undergoing malignant change is poor. Five of eight patients with follow-up (62%) died of disease with either residual (one patient) or metastatic tumor (four patients).

Divergent myosarcomatous differentiation in retroperitoneal liposarcoma.

We describe four patients with retroperitoneal liposarcomas undergoing myosarcomatous differentiation. The patients (two men and two women) were 47, 48, 68, and 72 years of age when first seen. The primary tumors were large retroperitoneal, well-differentiated liposarcomas, one featuring areas of dedifferentiation (without muscle elements). A myosarcomatous component became evident at the first recurrence in three cases and at the second recurrence in one. This component was always within dedifferentiated areas and in three of the cases coincided with the emergence of the latter. The muscle component had exclusively leiomyosarcomatous phenotype (alpha-smooth-muscle actin reactivity) in one case, exclusively rhabdomyosarcomatous phenotype (myoglobin reactivity) in two cases, and combined leiomyosarcomatous and rhabdomyosarcomatous phenotype (alpha-smooth-muscle actin and myoglobin) in one case. Ultrastructural studies of one of the tumors with a rhabdomyosarcomatous component revealed the presence of sarcomeres. Two patients died of extensive retroperitoneal disease, one patient died following the attempted removal of a recurrence, and one patient is alive and free of disease. These cases demonstrate that the dedifferentiated component of liposarcoma may exhibit a myosarcomatous component, a feature analogous to that previously described in dedifferentiated chondrosarcoma.

Ependymoma of the broad ligament. A report of two cases.

The clinical and pathological features of two cases of ependymoma that originated in the broad ligament are reported. Metastases developed in both patients. The tumors had the distinctive features of ependymoma on light-microscopical examination, and the diagnosis was confirmed by ultrastructural study in one case and immunoperoxidase staining for glial fibrillary acidic protein in both cases. The tumors presented diagnostic difficulties because of their close resemblance to serous papillary carcinomas of the ovary and the absence of published reports of ependymoma occurring in the female genital tract.

The purely epithelioid malignant peripheral nerve sheath tumor.

The purely epithelioid malignant peripheral nerve sheath tumor (PNST) is a rare form of PNT possibly first described by McCormack et al. in 1954. This tumor type is distinguishable from the glandular PNT and PNT with differentiated neuroepithelium (medulloepithelioma and neuroepithelioma) and differs from the ordinary epithelioid PNT because of the absence of a spindle cell component typical of malignant PNSTs. The two examples of purely epithelioid malignant PNT we describe arose in the popliteal fossa from the sciatic and tibial nerves of men with no definite evidence of von Recklinghausen's neurofibromatosis. Both tumors were partly mucinous, and so closely mimicked carcinoma and a few non-neurogenic myxoid sarcomas histologically that their final classification depended upon proof of a neural origin.

Visceral myogenic tumors. A manifestation of HIV infection in children.

We report a primary smooth-muscle tumor of undetermined malignant potential of the liver in a child with acquired immune deficiency syndrome (AIDS). This patient represents the eighth child infected with the human immunodeficiency virus who developed a mesenchymal tumor other than Kaposi's sarcoma. All these children were younger than 10 years of age. These tumors often were histologically or clinically malignant and all but one were smooth-muscle tumors. These tumors arose exclusively in visceral organs, and the hepatobiliary, gastrointestinal, and tracheopulmonary systems were involved. Transmission of the virus occurred both vertically (in six children) and via blood transfusion (in two). Given the rarity of smooth-muscle tumors in uninfected children, the unusual frequency of these tumors suggests that immunosuppression induced by the virus permits the unregulated proliferation of a primitive mesenchymal cell disposed to myogenous differentiation, a situation not unlike that observed in the development of AIDS-related Kaposi's sarcoma in adults.