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Undifferentiated sarcomas are primitive mesenchymal tumors that cannot be classified among standardized histopathologic entities. Whether they represent a homogeneous group with common histogenesis and clinical behavior or comprise a variety of tumors able to differentiate along specific maturative lineages is still debated. To identify prognostic and histogenetic markers, we analyzed 7 undifferentiated sarcomas (4 in the trunk and 3 in the extremities). Mean patient age was 7.5 years, and mean follow-up was 18 months. Two clinicopathologic subtypes emerged from this study. Four primitive mesenchymal undifferentiated sarcomas arose mainly on the trunk and very proximal extremities, had an aggressive clinical course with poor outcome (3 deaths from disease, 1 with persistent disease), and displayed sheets of oval cells, with bland nuclei. Three spindle cell undifferentiated sarcomas arose on the extremities, had a favorable outcome, and showed elongated spindle cells with areas of primitive fibrosarcoma. All were negative for epithelial membrane antigen, cytokeratins, CD34, smooth muscle actin, desmin,Myf4, and HMB45 and showed nuclear staining for INI. Focal staining for S100 and CD99 was found in 3 and 4, respectively. Among stem cell markers, CD117 was positive in 3 cases (1 primitive, 2 spindle), nestin in 5 cases (4 primitive, 1 spindle), and CD105-stained tumor cells lining newly formed vascular spaces in 4 cases (1 primitive, 3 spindle). Survivin was weakly expressed in 6 cases and reflected low levels of mRNA (median survivin/GAPDH ratio, 1.096). Cytogenetic analysis revealed nonspecific translocations in 3 tumors. No translocations associated with Ewing sarcoma, synovial sarcoma, or alveolar rhabdomyosarcoma were found. In summary, primitive undifferentiated sarcomas occur in the trunk, behave aggressively, and express nestin. Spindle cell undifferentiated sarcomas occur in extremities, have a favorable outcome, resemble fibrosarcomas, and have similarly low survivin levels and display CD105-positive vascular spaces, which may represent an early hemangiopericytomatous pattern.

FLI-1 nuclear transcription factor has been proposed as a useful tool in the differential diagnosis of small round cell sarcomas. Recently, FLI-1 has been reported as the first nuclear marker of endothelial differentiation. However, its clinical use has been hampered by major interpretation problems, due to the presence of background staining as well as staining variation between different lots of the same antiserum. In this study, a novel monoclonal antibody raised against the carboxyl terminal of the FLI-1 protein (clone GI146-222, BD Pharmingen) was tested in a series of small round cell and vascular neoplasms. Furthermore, in order to assess FLI-1 specificity, we analyzed its expression in a series of common epithelial and nonepithelial malignancies. In total, 15 Ewing's sarcomas, 10 rhabdomyosarcomas, 5 desmoplastic small round cell tumors, 10 synovial sarcomas, 10 high-grade pleomorphic sarcomas, 10 malignant melanomas, 5 Merkel's carcinomas, 10 colonic adenocarcinomas, 10 breast carcinomas, 10 lung adenocarcinomas, 20 angiosarcomas, 5 epithelioid hemangioendotheliomas, 10 Kaposi's sarcomas and 10 benign hemangiomas, were stained. A strong FLI-1 immunoreactivity was detected in all Ewing's sarcomas and vascular neoplasms, highlighting the high sensitivity of FLI-1 monoclonal antibody. However, 2/5 Merkel's carcinomas and 1/10 malignant melanomas showed a strong nuclear immunostaining, suggesting that FLI-1 may not be so helpful in the differential diagnosis of cutaneous Ewing's sarcoma. In addition, a weak immunoreactivity was found in 3/5 Merkel cell carcinomas, 3/10 synovial sarcomas, 5/10 malignant melanomas, 6/10 lung adenocarcinomas and in 1/10 breast carcinomas. In contrast, all the rhabdomyosarcomas, desmoplastic small round cell tumors, high-grade pleomorphic sarcomas and colonic adenocarcinomas tested were negative. Importantly, in contrast with previous studies, no background staining was observed. Our results indicate that FLI-1 monoclonal antibody can be reliably applied to the differential diagnosis of small round cell neoplasms of soft tissue, and confirm its important role as nuclear marker of endothelial differentiation, mainly helpful in those cases in which technical artifacts are seen by using the traditional membranous and cytoplasmic endothelial markers.

Sarcomas included in the broad group of small round-cell tumors (SRCT) and some non-SRCT lesions that typically are seen in pediatric-age patients can rarely occur in adults. However, there are differences in the anatomic sites that are involved and the prognosis in these two patient groups. The diagnosis of pediatric-type sarcomas in adults is often challenging because of the unusual contextual clinical setting and morphologic features. Immunohistochemical studies have greatly facilitated this process. Moreover, limited biomolecular studies that have been conducted have demonstrated comparable cytogenetic alterations in adults and children with pediatric-type tumors. They also have raised interesting questions concerning possible biological bases for differences in clinical behavior in the two cohorts. This review focuses on the morphological, immunohistochemical, and molecular characteristics of childhood-type sarcomas that affect adults, with emphasis on possible pitfalls in differential diagnosis.

Background: Undifferentiated (embryonal) sarcoma of the liver (UESL) is a rare childhood hepatic tumor, and it is generally considered an aggressive neoplasm with an unfavorable prognosis., Methods: The Soft Tissue Sarcoma Italian and German Cooperative Groups enrolled 17 children with UESL in studies conducted between 1979 and 1995. They were treated using the same multimodal approach as for patients with sarcomas including conservative surgery at diagnosis, multiagent chemotherapy, and second-look operation in cases of residual disease. Radiotherapy was occasionally used (2 of 17 patients)., Results: Twelve patients are alive with follow-up ranging from 2.4 to 20 years. Eight underwent complete tumor resection either at diagnosis or after preoperative chemotherapy, and all are currently alive. After initial chemotherapy tumor reduction was evident in six of nine evaluable cases. Overall three patients died of disease and one of a surgical complication. One child died in second complete remission for a non-disease-related cause., Conclusions: The current prognosis of UESL no longer should be regarded as poor. Modern multimodal treatment and supportive therapy have improved survival., (Copyright 2002 American Cancer Society.)

Malignant peripheral nerve sheath tumors (MPNSTs) are distinguished from a control group of typical benign schwannomas and neurofibromas on the basis of a set of quantitatively evaluated parameters, i.e., the cell density; the number of mitoses and apoptotic bodies; the nuclear area and shape; the number and absolute and relative areas of silver-staining nucleolar organizer regions; necrosis; and angiogenesis. Only the extent of tumor necrosis, the mitotic rate, and the parameters related to silver-staining nucleolar organizer regions discriminate between less aggressive MPNSTs (disease-free patients after 4 years of follow-up) and more aggressive MPNSTs (with recurrences or metastases during the first 4 years of follow-up).

Background: Locoregional control of soft tissue sarcomas of the limbs is achieved generally using a multidisciplinary approach consisting of conservative surgery combined with radiation therapy, intraarterial chemotherapy, or hyperthermic antiblastic perfusion (HAP). Before surgery, HAP seems to be the more suitable tool in decreasing tumor mass and allowing limb-sparing surgery. The authors' aim was to ascertain the activity of HAP with doxorubicin against intermediate or high grade limb tumors., Methods: In 23 patients with limb sarcomas (2 patients International Union Against Cancer Stage IIA, 4 stage IIB, 1 stage IIIA, 11 stage IIIB, and 5 stage IVB) doxorubicin was administered via HAP 4-6 weeks before surgery. The drug (bolus, 0.7-1.4 mg/kg) was perfused for 60 minutes with a tumor temperature of at least 40.5 degrees C (range, 40.5-42.6 degrees). Tumor necrosis was then assessed radiologically and pathologically., Results: Systemic toxicity was hematologic grade (G) 2 in 2 patients, gastrointestinal (hepatic) in 6, G1 in 2, G2 in 3, and G3 in 1; 2 patients had alopecia; locoregional toxicity (graded according to Wieberdink) was G1 or G2 in 18, G3 in 4, and G4 in 1. Tumor necrosis was more than 50% in 17 patients (74%). Limb-sparing surgery was feasible in 20 patients (91%). At present, 14 patients are alive. Six had local recurrences, and eight had distant metastases., Conclusions: Our findings show that HAP with doxorubicin is an active and well-tolerated procedure within a multidisciplinary approach to treatment of limb sarcomas.

We here report on our 10-year experience of surgery in 25 patients with primary retroperitoneal sarcoma and make an appraisal of the more effective available clinical approach. Ten patients had leiomyosarcoma, eight liposarcoma, and seven had other tumor types. Histological grading was G1 in seven patients, G2 in six patients and G3 in 12. Ten patients (40%) underwent wide tumor excision, five (20%) marginal excision, four (16%) partial excision and six (24%) wedge biopsy at laparotomy. Adjacent organ resection was required in 10 of the 15 patients who underwent wide or marginal resection, seven of whom had adjuvant chemoradiotherapy. After wide resection, local recurrences were observed in 2/10 patients; the 10-year survival rate was 33%. Three out of five patients who underwent marginal resection had local recurrences; one is alive 10 years after surgery and chemo-radiotherapy. Histological grading was the most important prognostic factor. Radical resection is the only effective available treatment for retroperitoneal sarcomas, and patients with low-grade tumors benefit most from it with respect to survival and local recurrence rate. The efficacy of adjuvant treatment has yet to be clarified.