Multiscale-omic assessment of EWSR1-NFATc2 fusion positive sarcomas identifies the mTOR pathway as a potential therapeutic target

Sarcomas harboring EWSR1-NFATc2 fusions have historically been categorized and treated as Ewing sarcoma. Emerging evidence suggests unique molecular characteristics and chemotherapy sensitivities in EWSR1-NFATc2 fusion positive sarcomas. Comprehensive genomic profiles of 1024 EWSR1 fusion positive sarcomas, including 14 EWSR1-NFATc2 fusions, were identified in the FoundationCore® database. Additional data from the Gene Expression Omnibus, the Genomics of Drug Sensitivity in Cancer and The Cancer Genome Atlas datasets were included for analysis. EWSR1-NFATc2 fusion positive sarcomas were genomically distinct from traditional Ewing sarcoma and demonstrated upregulation of the mTOR pathway. We also present a case of a 58-year-old male patient with metastatic EWSR1-NFATc2 fusion positive sarcoma who achieved 47 months of disease stabilization when treated with combination mTOR and VEGF inhibition. EWSR1-NFATc2 fusion positive sarcomas are molecularly distinct entities with overactive mTOR signaling; which may be therapeutically targetable. These findings support the use of precision medicine in the Ewing family of tumors.

Successful Radical Pneumonectomy for a Primitive Neuroendodermal Tumor in the Lung: A Case Report and Review of the Literature

Peripheral primitive neuroendodermal tumors (PNETs) and Ewing's sarcoma belong to the Ewing family of tumors and are small round-cell malignancies originating from spinal cord cells. These tumors account for 5% of all small round-cell malignant neoplasms. PNETs that arise from the lung parenchyma without pleural or chest wall involvement are very rare. We report a case of an adult female with a large pulmonary PNET who had given birth just 1 month prior to the diagnosis. She had cough and expectoration for 6 months, and the preoperative examination showed no metastases. Thus, we performed radical pneumonectomy and lymph node dissection. The patient recovered well without surgical complications and was discharged 7 days after the surgery. Postoperative pathology confirmed that the tumor was a small round-cell malignancy, and the tumor cells were positive for CD99, Friend leukemia virus integration 1 (FLI-1), and neuron-specific enolase (NSE), which was consistent with the diagnosis of a PNET. For primary large pulmonary PNETs, radical pneumonectomy may be a safe surgical method, worthy of further application in clinical practice.

Ewing Sarcoma/Primitive Neuroectodermal Tumors In The Mediastinum: A Case Report And Review Of Literature

Ewing Sarcoma/Primitive Neuroectodermal Tumors (ES/PNETs) are highly malignant neoplasms originating from primitive neural tube embryonic cells, and grouped in the Ewing family of tumors. These malignancies are relatively uncommon, most frequently arising from bones or soft tissues and rarely reported in the mediastinum. The present study describes a case of a 22-year-old woman with unresectable ES/PENT in the middle mediastinum. The patient died the next day after bronchoscopy. A review of the literature showed reports of 9 patients with mediastinal PENTs in the past 20 years. The therapy of choice for ES/PENT in mediastinum consists of combinations of surgical excision with neoadjuvant or adjuvant chemotherapy and radiation to improve event-free survival rates.

An EWSR1-CREB3L1 Fusion Gene in Extraskeletal Undifferentiated Round Cell Sarcoma Expands the Spectrum of Genetic Landscape in the “Ewing-Like” Undifferentiated Round Cell Sarcomas

The molecular findings in Ewing sarcoma have greatly expanded in recent years. Furthermore, this is particularly true for the subset termed “Ewing-like” undifferentiated round cell sarcomas in which new translocations have been reported since the fourth edition of the WHO Classification of Tumours of Soft Tissue and Bone. Amid this expanding genetic landscape, we report a case of extraskeletal undifferentiated round cell “Ewing-like” sarcoma in a 27-year-old female. The patient presented with a large lung mass accompanied on staging imaging by deposits suspicious for metastatic disease in the humerus, calvarium, and lymph nodes of the neck and chest. Biopsy of the lung mass revealed a densely packed monotonous proliferation of round, uniform neoplastic cells with scant cytoplasm. By immunohistochemistry, the tumor cells were diffusely positive for CD99, synaptophysin, TLE1, EMA, and MUC4 and negative for FLI1, PAX7, AE1/3, S100, SOX10, WT1, p63, desmin, and HMB45. Fluorescence in situ hybridization demonstrated rearrangement of the EWSR1 gene. Next-generation sequencing based assay revealed an EWSR1-CREB3L1 fusion. Taken together, the histomorphologic and molecular findings were considered consistent with an undifferentiated round cell sarcoma with an EWSR1-CREB3L1 fusion. Although described in entities such as sclerosing epithelioid fibrosarcoma, low-grade fibromyxoid sarcoma, and small cell osteosarcoma, this has not been previously described in undifferentiated round cell (“Ewing-like”) sarcoma. This finding adds to the growing list of undifferentiated round cell sarcomas with Ewing-like morphologic phenotype–associated fusion genes and may contribute to further defining and characterizing the different subset of tumors in the Ewing family of tumors.

Highly aggressive undifferentiated small round blue cell tumor of foot with unique SMARCA1, KAT6A and NAV3 mutations

ABSTRACT Malignancies characterized histologically by high-grade monotonous small round blue cells (SRBCs) belong to a heterogeneous group of neoplasms often referred to as Ewing family of tumors. The most common molecular confirmation of these neoplasms is by fusions between EWSR1 gene on chromosome 22 and the ETS family of transcription factors, including FLI1 gene (11q24) and the ERG (21q22), that are implicated in the development of different tissues as well as cancer progression. In this article, we present a case of highly aggressive extraskeletal SRBC tumor involving the foot of a 24-year-old male with sole molecular findings of mutations in KAT6A, NAV3 and SMARCA1 genes with high expression of soft tissue markers (COL1A1, COL1A2, COL3A1) and MYC mRNA. To our knowledge, this unique mutational pattern has not previously been described in SRBCs.