Round Cell Tumors of Bone

Long-term follow-up of 15 patients with non-metastatic Ewing's sarcoma and a skip lesion

BACKGROUND Skip lesions in Ewing's sarcoma of the bone seem to be rare; to our knowledge only 7 cases have been published in the English medical literature.

METHODS

We retrospectively reviewed imaging and histological data relating to 235 patients with non-metastatic Ewing's sarcoma of the bone who participated in the cooperative Ewing's sarcoma study (CESS 86 and CESS 91), and we identified 15 patients with a skip lesion at diagnosis.

RESULTS

The skip lesion was located in the same bone as the primary tumor in 13 patients, and in an adjacent juxtaarticular bone in 2 cases. The average follow-up was 11 years. Despite aggressive treatment including surgery in all cases, tumor relapse occurred in 9 patients, and 7 of these patients died due to metastatic disease.

INTERPRETATION

Skip lesions in patients with otherwise non-metastatic skeletal Ewing's sarcoma may be of the same consequence as the molecular detection of marrow metastases and possibly confer a worse prognosis. Newer imaging modalities (for example PET) and careful staging work-up may indicate that skip metastases in Ewing's sarcoma are more common than previously suspected.

Pathologic and molecular aspects of soft tissue sarcomas

This article retains the conventional approach to the classification of soft tissue sarcomas, dividing them into several major histogenetic categories based on their overall microscopic appearance, tissue differentiation pattern, and biologic potential. The author advocates a multimodal approach, in which four distinctive data sets--clinical, radiographic, microscopic, and, in some cases, molecular--are considered to establish the diagnosis and treatment plan. Such step-wise analysis is more likely to lead to consistency and accuracy as compared with an intuitive approach based on fragmentary data. The author describes individual lesions of soft tissue as clinicopathologic entities and believes that they can be more accurately diagnosed and appropriately treated with the help of data generated by a multidisciplinary team. In addition, this article emphasizes the need to use emerging molecular techniques that can provide important clues for both diagnosis and prognosis.

Neoadjuvant chemotherapy for peripheral malignant neuroectodermal tumor of bone: recent experience at the istituto rizzoli

PURPOSE

The results achieved in 44 patients with nonmetastatic peripheral neuroectodermal tumor (PNET) of bone treated with neoadjuvant chemotherapy are reported.

PATIENTS AND METHODS

A six-drug regimen of chemotherapy (vincristine, doxorubicin, dactinomycin, cyclophosphamide, ifosfamide, and etoposide) was administered to all patients. Local treatment consisted of surgery in 20 patients, surgery followed by radiotherapy in 13, and radiotherapy only in 11.

RESULTS

At a mean follow-up of 4.5 years (range, 2 to 7 years), 23 patients (52%) remain event-free, 20 have relapsed (45%), and one has died of chemotherapy-related toxicity. The 5-year event-free survival and overall survival were 54.2% and 62.7%, respectively. To assess the prognostic significance of neural differentiation in the family of Ewing's sarcoma, these results have been compared with the outcomes of 138 concomitant patients with typical Ewing's sarcoma (TES) who were treated according to the same protocol. Of these, 103 (75%) remained continuously event-free, 34 (24%) relapsed, and one died of chemotherapy-related toxicity. It follows that PNET patients treated with this chemotherapy regimen have a significantly worse prognosis than typical ES patients (5-year event-free survival, 54.2% v 70.6%, P <.012; 5-year overall survival, 62.7% v 78.3%, P <.002).

CONCLUSION

The authors conclude that studies into new adjuvant therapy for Ewing's sarcoma modulated according to risk of relapse should also consider neural differentiation as a risk factor.

Evaluation of prognostic factors in a tumor volume-adapted treatment strategy for localized Ewing sarcoma of bone: the CESS 86 experience. Cooperative Ewing Sarcoma Study

BACKGROUND

The Cooperative Ewing Sarcoma Study (CESS 86), conducted by the German Society of Pediatric Oncology and Hematology (GPOH), was planned on the basis of the results of the preceding CESS 81 study. The prognostic significance of tumor volume in localized Ewing sarcoma of bone was well documented in the CESS 81 trial. As a consequence, the treatment intensity was adapted to volume in the follow-up CESS 86 trial: the four-drug combination used in CESS 81 was amended for patients with large tumor volume (> or = 100 ml), where ifosfamide was substituted for cyclophosphamide.

PROCEDURE

From January 1986 to June 1991, 177 protocol patients with localized Ewing sarcoma of bone were registered in CESS 86. The prognostic implication of tumor volume and several covariates was evaluated using Kaplan-Meier life table analysis and Cox's proportional hazard model.

RESULTS

The estimated 5- and 8-year event-free survival (EFS) rates were both 59%. Age, gender, tumor site, and a tumor volume of 100 ml did not distinguish groups of patients with different prognosis. However, the prognosis of patients with tumors >200 ml (8-year EFS rate: 42%) was significantly inferior compared to patients with tumors both of 100 to 200 ml (70%) and of <100 ml (63%). In contrast to CESS 81, the histological response to chemotherapy was no longer a significant prognostic factor (EFS: 64% for good and 50% for poor responders, respectively).

CONCLUSIONS

Despite risk-adapted treatment intensity, tumor volume retained its prognostic significance; the cut point, however, was shifted toward larger volumes.

Ganglion cells in Ewing's sarcoma following chemotherapy: a case report

A case of Ewing's sarcoma of the bone, arising in the right radius of a 12-year-old girl, which showed unique histologic features after pre-operative treatment, is reported. The light microscopic features of a biopsy sample were those of a small round cell tumor showing positive immunoreaction with antibodies against the product of the MIC 2 gene (O13), neuron-specific enolase, neurofilament, and synaptophysin, but no morphological differentiation. The patient received combined intensive multi-drug chemotherapy and radiation before surgery. Examination of the surgical specimen showed that the tumor was less cellular than that in the biopsy specimen, and was composed mainly of loosely textured large cells mimicking ganglion cells, occasionally forming Homer-Wright rosettes. An immunohistochemical study revealed that neural differentiation was enhanced. Immunoreactivity for Leu-7 also became positive. Although the patient underwent postoperative chemotherapy, she died of multiple lung and bone metastases 30 months after the diagnosis. Autopsy showed that metastatic foci were made up of densely packed small round cells like those seen in the biopsy samples, but associated with prominent Homer-Wright rosettes. To the authors' knowledge, this is the first report of a tumor being replaced almost entirely by ganglion cells after pre-operative chemotherapy and radiotherapy.

p53 and ras mutations in Ewing's sarcoma

The role of tumor suppressor genes and oncogenes in the development of Ewing's sarcoma has not yet been fully clarified. In this study, we analyzed the frequency of p53 tumor suppressor gene mutation in exons 4-8 by PCR-SSCP and direct sequencing, and the expression of p53-protein in Ewing's sarcoma (ES) by using immunohistochemistry. The overexpression of MDM2, which acts as a functional inactivator of p53, was studied by immunohistochemistry. In addition, a screening for point mutations in the hot spot regions codon 12 and 13 of exon 1 and codon 61 of exon 2 of ras-genes (H-ras, N-ras, K-ras) was performed. In one case, a p53 gene mutation could be confirmed in codon 238 of exon 7 (1/24). Overexpression of MDM2 was found in five cases; in ras-genes, no mutations were detected. Compared with other highly malignant mesenchymal pediatric tumors such as osteosarcomas, mutations of p53 and ras in Ewing's sarcomas are an extraordinarily rare event. However, their frequency is comparable to that of PNET, suggesting that the low incidence of these mutations in ES and PNET could be group-specific for tumors of neuroectodermal genesis.

Molecular diagnosis of Ewing tumors: improved detection of EWS-FLI-1 and EWS-ERG chimeric transcripts and rapid determination of exon combinations

Most Ewing tumors (ET), including Ewing sarcomas, peripheral primitive neuroectodermal tumors (PNET), and Askin's tumors, can be defined according to the specific chromosomal translocations t(11;22)(q24;q12) (EWS-FLI-1) or t(21;22)(q21;q12) (EWS-ERG). Detection of the chimeric RNA transcripts by reverse transcriptase-polymerase chain reaction (RT-PCR) has greatly facilitated the diagnosis of ET. Because of variable chromosomal breakpoint locations, however, the EWS gene fusions with FLI-1 and ERG genes are highly heterogenous, resulting in different sizes of the amplification products. To improve the diagnostic usefulness of the RT-PCR assay, we have developed an assay to detect chimeric mRNA transcripts by nested RT-PCR, followed by digestion of the PCR fragments with three different restriction endonucleases. This allows confirmation of the specificity of the PCR product and provides a rapid method to determine the combination of exons present in a transcript. In the 12 Ewing tumors tested, five different exon combinations were detected. In nine repeat biopsies of four patients, the case-specific translocation remained unchanged. One additional central PNET had no ET-specific translocation. In conclusion, the suggested combination of RT-PCR and restriction analysis of the PCR products allows a rapid and specific determination of ET-specific translocations.

Significance of surgical margin on the prognosis of patients with Ewing's sarcoma. A report from the Cooperative Ewing's Sarcoma Study

BACKGROUND

There is little information regarding an adequate surgical margin for local control of Ewing's sarcoma.

METHODS

Two hundred and forty-four patients (PTS) with Ewing's sarcoma who were registered in the Cooperative Ewing's Sarcoma Studies underwent surgical treatment. Ninety-four PTS underwent definitive surgery (surgery alone), 131 PTS received postoperative irradiation, and 19 PTS received preoperative irradiation. The surgical margins were distributed as follows: radical, 29 PTS; wide, 148 PTS; marginal, 39 PTS; and intralesional, 28 PTS. The impact of the surgical margin on the treatment outcome of PTS was analyzed statistically.

RESULTS

The local or combined (local recurrence and systemic metastasis) relapse rate after surgery with or without irradiation was significantly lower compared with that after definitive irradiation (irradiation alone) (7% vs. 31%, P < 0.0001). The local or combined relapse rate after complete resection (radical or wide margin) with or without irradiation was less compared with that after incomplete resection (marginal or intralesional margin) with or without irradiation (5% vs. 12% P = 0.0455). The local or combined relapse rate did not greatly decreased after irradiation after incomplete surgery (from 14% to 12%). In both groups of good (viable tumor cells < 10%) and poor (viable cells > or = 10%) histologic response, the difference in systemic or combined relapse rate between patients undergoing complete and incomplete surgery was not significant. The 10-year overall survival of the PTS for each of the margins was distributed as follows: radical, 58%; wide, 65%; marginal, 61%; and intralesional, 71% (P = not significant).

CONCLUSIONS

Surgery in patients with Ewing's sarcoma adds to the safety of local control. Under the current treatment regimen with intensive chemotherapy and irradiation, complete resection of the tumor appears capable of decreasing the risk of local recurrence.