Periosteal Ewing sarcoma family of tumors of the femur confirmed by molecular detection of EWS-FLI1 fusion gene transcripts: a case report and review of the literature

Periosteal Ewing Sarcoma with Distant Metastases: Report of Two Patients and Review of the Literature

Periosteal Ewing sarcoma (ES) is an exceedingly rare topographic subtype of the ES. To our knowledge, only 60 patients have been reported in the medical English language literature. It predominantly affects men in the second decade of life and arises in the long tubular bone diaphysis. Periosteal ES rarely develops distant metastases. We report two patients of this rare ES location that were found on the distal tibial shaft and proximal femoral diaphysis of a 21-year-old man and an 8-year-old boy, respectively. Both patients were treated with neoadjuvant chemotherapy, wide resection, and adjuvant chemotherapy. One of our patients had lung metastases at the time of diagnosis and died 5 years later. The other patient presented intramedullary humeral bone metastasis 19 years after diagnosis. There has been no evidence of disease in the 26 years of follow-up. Close follow-up of periosteal ES is recommended because distant metastases may exceptionally occur, even several years after diagnosis.

Periosteal Ewing Sarcoma: Imaging Features and Clinical Outcomes in 7 Patients

OBJECTIVE

The aim of this study was to describe imaging features, treatment, and prognosis of patients with periosteal Ewing sarcoma (PES).

MATERIALS AND METHODS

Seven patients with PES treated between 2001 and 2020 were studied retrospectively for presenting symptoms, imaging features, treatment, and prognosis.

RESULTS

Among the 7 patients (mean age, 27.3 years) with local pain and/or mass of less than 6 months duration, 4 were males and 3 females (1.3:1). These surface tumors involved 3 long bones and 4 pelvic bones. Radiographs showed cortical erosions with 2 and CT with 4 long bone tumors. All 7 surface tumors showed normal marrow on MRI, and 4 tumors demonstrated normal marrow activity on 18FFDG fluorodeoxyglucose PET-CT. The only exception was a PES involving iliac bone with thin cortex and marrow extension, which demonstrated hypermetabolic marrow activity. All patients were treated initially with chemotherapy and optional radiation treatment with complete tumor resolution of a tibial PES in 1 patient. The remaining 2 patients with long bone PES had tumor resection and limb-salvage surgery and the 4 patients with pelvic bone PES had hemipelvectomy after chemotherapy/radiation treatment. Five patients were disease-free with long-term survival. A patient with a long bone PES and solitary lung metastasis at onset had tumor resection and metastasectomy with complete recovery without tumor recurrence. The 2 patients with pubic bone PES had complete recovery without tumor recurrence; however, the remaining 2 patients with iliac bone PES developed distant metastases and died within 2 years of diagnosis.

CONCLUSIONS

Periosteal Ewing sarcoma arises in periosteum of bone and spares medullary cavity. As compared with its intramedullary counterpart, the tumor has better prognosis with long-term survival. Rarely, the surface tumor arising at a bone with thin cortex, such as iliac bone or scapula, may have medullary involvement. We have described our experience in diagnosis and clinical management in 7 patients of this rare surface variant of the more common intramedullary Ewing sarcoma.

Intramedullary, periosteal, and extraskeletal Ewing sarcomas: retrospective study of a series of 126 cases in a reference center

OBJECTIVE

To evaluate the proportion of extraskeletal, periosteal, and intramedullary Ewing sarcomas among musculoskeletal Ewing sarcomas.

MATERIAL AND METHOD

Our single-center retrospective study included patients with musculoskeletal Ewing sarcoma diagnosed between 2005 and 2019 in our pathology center (cases from our adult bone tumor referral center and adult and pediatric cases referred for review). Recurrences, metastases, and visceral Ewing sarcomas were excluded. Intramedullary Ewing sarcomas were defined by involvement of the medullary cavity. Periosteal cases were defined by involvement of the subperiosteal area without extension to the medullary cavity. Extraskeletal cases were defined by the absence of involvement of the bone tissue and the subperiosteal area.

RESULTS

Our series included 126 patients with musculoskeletal Ewing sarcoma, including 118 skeletal Ewing sarcomas (93.7%) and 8 extraskeletal Ewing sarcomas (6.3%). Of the 118 skeletal Ewing sarcomas 112 were intramedullary (88.9%) and 6 were periosteal (4.8%). Extraskeletal Ewing sarcomas were more common in women and in patients older than 40 (p < 0.05).

DISCUSSION

The 6.3% proportion of extraskeletal Ewing sarcoma is lower than the median of 30% estimated from the literature. This difference could be explained by an overestimation of extraskeletal Ewing sarcomas of the chest wall (Askin tumors), an underestimation of periosteal cases confused with extraskeletal cases, and the presence of "Ewing-like" soft tissue sarcomas in previous series. Because of its prognostic and therapeutic impact, the distinction of morphologic subtypes requires the cooperation of experienced radiologists and pathologists.

A review of imaging of surface sarcomas of bone

Surface lesions of bone are uncommon. Although their imaging features generally mirror those of their intramedullary counterparts, surface lesions may demonstrate distinct characteristics which along with their unusual location present a diagnostic challenge. Surface sarcomas are usually of a lower grade compared with intramedullary variants, leading to differences in management. Osteosarcoma arising from the cortical surface of the bone is termed juxtacortical or surface osteosarcoma and includes three distinct entities: parosteal, periosteal, and high-grade surface osteosarcoma. We also review the features intracortical osteosarcoma, which some authors include under the umbrella term surface osteosarcoma. These lesions exhibit biologic features distinct from those of conventional intramedullary osteosarcoma, which underlines the importance of accurate imaging diagnosis. Periosteal chondrosarcoma and periosteal Ewing sarcoma also have distinctive imaging appearances. The purpose of this article is to review surface sarcomas of bone with regard to their clinical and radiological features and to discuss the differential diagnosis for each condition.

Periosteal Ewing Sarcoma in a 65-Year-Old Man: A Case Report

CASE

Ewing sarcoma is predominantly a pediatric bone malignancy involving the medullary canal. Periosteal Ewing sarcoma, a subtype arising from the periosteum, is exceedingly rare, with approximately 30 reported cases in the literature. We describe a case of periosteal Ewing sarcoma in the tibia of a 65-year-old man. Magnetic resonance imaging revealed a heterogeneous mass in the proximal tibial diaphysis without medullary involvement. The diagnosis was confirmed histologically after biopsy. The patient was treated with neoadjuvant chemotherapy, radical resection, and adjuvant chemotherapy.

CONCLUSION

To the best of our knowledge, this case report describes the oldest documented patient with periosteal Ewing sarcoma.

Identifying and analyzing different cancer subtypes using RNA-seq data of blood platelets

Detection and diagnosis of cancer are especially important for early prevention and effective treatments. Traditional methods of cancer detection are usually time-consuming and expensive. Liquid biopsy, a newly proposed noninvasive detection approach, can promote the accuracy and decrease the cost of detection according to a personalized expression profile. However, few studies have been performed to analyze this type of data, which can promote more effective methods for detection of different cancer subtypes. In this study, we applied some reliable machine learning algorithms to analyze data retrieved from patients who had one of six cancer subtypes (breast cancer, colorectal cancer, glioblastoma, hepatobiliary cancer, lung cancer and pancreatic cancer) as well as healthy persons. Quantitative gene expression profiles were used to encode each sample. Then, they were analyzed by the maximum relevance minimum redundancy method. Two feature lists were obtained in which genes were ranked rigorously. The incremental feature selection method was applied to the mRMR feature list to extract the optimal feature subset, which can be used in the support vector machine algorithm to determine the best performance for the detection of cancer subtypes and healthy controls. The ten-fold cross-validation for the constructed optimal classification model yielded an overall accuracy of 0.751. On the other hand, we extracted the top eighteen features (genes), including TTN, RHOH, RPS20, TRBC2, in another feature list, the MaxRel feature list, and performed a detailed analysis of them. The results indicated that these genes could be important biomarkers for discriminating different cancer subtypes and healthy controls.