Differentiation of myxoid liposarcoma by magnetic resonance imaging: a histopathologic correlation.

BACKGROUND: Myxoid liposarcomas represent a heterogeneous group of soft tissue tumors in which prognosis is dependent on differentiation. PURPOSE: To identify magnetic resonance imaging (MRI) criteria to distinguish low-grade from high-grade myxoid liposarcomas. MATERIAL AND METHODS: MR images of 30 histologically proven myxoid liposarcomas were retrospectively reviewed. Tumors were evaluated according to size, localization, tumor border, and structure as well as tumor composition. These imaging criteria were correlated with histopathological findings. RESULTS: Nineteen myxoid liposarcomas were histologically classified as low-grade myxoid liposarcomas, whereas 11 were considered high-grade myxoid liposarcomas. Mean tumor volume of low-grade myxoid liposarcomas (710.1 ± 960.1 ccm) was significantly smaller as compared to high-grade myxoid liposarcomas (2737.0 ± 3423.7 ccm; P = 0.04). In addition to necrotic areas, three tumor components - fatty, myxoid, as well as contrast-enhancing non-fatty, non-myxoid - could be identified. The mean fraction of fatty tumor areas in low-grade myxoid liposarcomas was 10 ± 11% as compared to 6 ± 4% for high-grade myxoid liposarcomas (P = 0.66). Myxoid components accounted for 88 ± 16% in low-grade myxoid liposarcomas, but only for 45 ± 25% in high-grade myxoid liposarcomas (P < 0.0001). The non-fatty, non-myxoid tumor fraction was significantly higher in high-grade myxoid liposarcomas (50 ± 25%) as compared to low-grade myxoid liposarcomas (2 ± 9%; P < 0.0001). A proportion of > 5% of this tumor fraction was found to be a precise unique predictor for high-grade myxoid liposarcomas with a sensitivity of 100% and a specificity of 95%. CONCLUSION: Tumor components with contrast-enhancing non-fatty, non-myxoid imaging features were predominantly found in high-grade myxoid liposarcomas, which may histologically resemble round cell clusters.

The influence of tumor- and treatment-related factors on the development of local recurrence in osteosarcoma after adequate surgery. An analysis of 1355 patients treated on neoadjuvant Cooperative Osteosarcoma Study Group protocols.

BACKGROUND: Local recurrence (LR) in osteosarcoma is associated with very poor prognosis. We sought to evaluate which factors correlate with LR in patients who achieved complete surgical remission with adequate margins. PATIENTS AND METHODS: We analyzed 1355 patients with previously untreated high-grade central osteosarcoma of the extremities, the shoulder and the pelvis registered in neoadjuvant Cooperative Osteosarcoma Study Group trials between 1986 and 2005. Seventy-six patients developed LR. RESULTS: Median follow-up was 5.56 years. No participation in a study, pelvic tumor site, limb-sparing surgery, soft tissue infiltration beyond the periosteum, poor response to neoadjuvant chemotherapy, failure to complete the planned chemotherapy protocol and biopsy at a center other than the one performing the tumor resection were significantly associated with a higher LR rate. No differences were found for varying surgical margin widths. Surgical treatment at centers with small patient volume and additional surgery in the primary tumor area, other than biopsy and tumor resection, were significantly associated with a higher rate of ablative surgery. CONCLUSIONS: Patient enrollment in clinical trials and performing the biopsy at experienced institutions capable of undertaking the tumor resection without compromising the oncological and functional outcome should be pursued in the future.

[Endoprosthesis in the operative treatment of bone tumours of the pelvis]. / Stellenwert der Beckenendoprothetik in der operativen Therapie von Tumoren des knöchernen Beckens.

AIM: Limb salvage procedures in cases of bone tumours of the pelvis are established. In this retrospective study the clinical results after implantation of megaprostheses of the pelvis are reported. METHODS: Between November 1994 and September 2004 an endoprosthetic replacement of the pelvis was performed in 24 consecutive patients, fourteen females and ten males. The mean age was 49.3 years (range: 17-64 years). In ten cases a complete and in fourteen an incomplete internal hemipelvectomy was done. Thirteen patients presented with a primary bone tumour and eleven with a bone metastasis. The tumour volume ranged between 50 and 1315 ml (median: 352 ml). The mean follow-up was 98 months. RESULTS: In 23 of the 24 patients an R0 resection was achieved. Local recurrences were observed in five patients (20.8%). Deep infections developed in ten patients (41.7%) postoperatively. In two of these ten patients a secondary external hemipelvectomy was necessary. Eight patients (33.3%) developed a paralysis of the femoral and/or sciatic nerve, and a loosening of the endoprosthesis was observed in four cases (16.7%). Two patients died within 30 days postoperatively (pulmonary embolism, dissection of the abdominal aorta). Eight of the 24 patients are still alive, two of them after secondary hemipelvectomy and another after removal of the endoprosthesis due to infection. The functional results of the five surviving patients with an endoprosthesis, according to the MSTS scoring system, are good in two and poor in three patients. CONCLUSION: Internal hemipelvectomy and reconstruction of the pelvic girdle with endoprostheses is associated with a high rate of complications. Each single case should be critically evaluated and alternative procedures should be considered.