Extra-osseous Ewing sarcoma of the pancreas: case report with radiologic, pathologic, and molecular correlation, and brief review of the literature

Ewing sarcoma of the pancreas: a pediatric case report and narrative literature review

Ewing's Sarcoma (ES) is an rare, small round-cell sarcoma that predominantly occurs in children and young adults, with both skeletal and extraskeletal manifestations. However, pancreatic ES, due to its rarity, is infrequently featured in scholarly literature, with only a scant 43 reported instances. Our study describes a case of pancreatic ES in an 8-year-old boy who was found to have an abdominal mass. Following an exhaustive examination, the boy was diagnosed with a neoplasm in the pancreatic head and underwent a complex surgical procedure encompassing pancreatoduodenectomy and partial transverse colectomy. Immunohistochemical assays confirmed the neoplastic cells' positivity for Cluster of Differentiation 99(CD99), Vimentin, and NK2 Homeobox 2(NKX2.2), while genomic testing identified an EWSR1-FLI1(Ewing Sarcoma Breakpoint Region 1-Friend Leukemia Integration 1) gene fusion. This led to a conclusive diagnosis of pancreatic Ewing's Sarcoma. The patient underwent seven cycles of adjuvant chemotherapy, alternating between VDC (Vincristine, Doxorubicin, Cyclophosphamide) and IE (Ifosfamide, Etoposide) tri-weekly, but did not undergo radiotherapy. At present, the patient remains neoplasm-free. Through our case analysis and comprehensive review of the existing literature, we aim to underscore th rarity of pancreatic Ewing's sarcoma and to highlight the efficacy of our individualized therapeutic approach.

Extraosseous Ewing's sarcoma of the pancreas

We present the clinical case of a 21-year-old male with abdominal pain in the left hypochondrium radiating to the ipsilateral lumbar area and a weight loss of 2kg over a month, secondary to a large palpable intra-abdominal mass in the examination. TAC revealed a large solid mass with necrotic-cystic component which depended of the pancreas, infiltrated the spleen, enveloped the celiac trunk and affected to the splenic vases. Inmunohistochemical and molecular study confirmed the diagnosis extraosseus Ewing sarcoma (EES).

Pancreatic Masses in Children and Young Adults: Multimodality Review with Pathologic Correlation

Masses and masslike lesions of the pancreas are uncommon in the pediatric population. However, owing to overlapping clinical and imaging features, it can be challenging to differentiate the various causes of pediatric pancreatic masses at initial patient presentation. Clinical data such as patient age, signs and symptoms at presentation, laboratory test results, and potential underlying cancer predisposition syndrome can be helpful when formulating a differential diagnosis. US may be the first imaging study to depict a pancreatic mass in a child, as this examination is frequently performed in children with nonspecific abdominal signs and symptoms because of its wide availability and relatively low cost and the lack of a need for sedation or anesthesia. CT or MRI is typically required for more thorough characterization of the mass and surgical planning. Complete characterization of pancreatic masses includes assessment of vascular involvement, local invasion, and extrapancreatic spread of tumor. The authors provide an up-to-date comprehensive review of the clinical manifestations, histopathologic features, and imaging findings of primary and secondary tumors of the pancreas in children and young adults. Advances in imaging, current prognostic information, and treatment paradigms also are highlighted. Finally, nontumorous masslike lesions of the pediatric pancreas, including vascular malformations, cystic disorders (eg, von Hippel-Lindau syndrome, cystic fibrosis), intrapancreatic accessory spleen, and autoimmune pancreatitis, are discussed. Online supplemental material is available for this article. ^©RSNA, 2021.

Rationale for Early Detection of EWSR1 Translocation-Associated Sarcoma Biomarkers in Liquid Biopsy

Sarcomas are mesenchymal tumours that often arise and develop as a result of chromosomal translocations, and for several forms of sarcoma the EWSR1 gene is a frequent translocation partner. Sarcomas are a rare form of malignancy, which arguably have a proportionally greater societal burden that their prevalence would suggest, as they are more common in young people, with survivors prone to lifelong disability. For most forms of sarcoma, histological diagnosis is confirmed by molecular techniques such as FISH or RT-PCR. Surveillance after surgical excision, or ablation by radiation or chemotherapy, has remained relatively unchanged for decades, but recent developments in molecular biology have accelerated the progress towards routine analysis of liquid biopsies of peripheral blood. The potential to detect evidence of residual disease or metastasis in the blood has been demonstrated by several groups but remains unrealized as a routine diagnostic for relapse during remission, for disease monitoring during treatment, and for the detection of occult, residual disease at the end of therapy. An update is provided on research relevant to the improvement of the early detection of relapse in sarcomas with EWSR1-associated translocations, in the contexts of biology, diagnosis, and liquid biopsy.

Primary pancreatic Ewing sarcoma: a cytomorphologic and histopathologic study of 13 cases

INTRODUCTION

Ewing sarcoma (ES) is a small, round cell sarcoma that rarely occurs in solid organs, including the pancreas. A diagnostic overlap exists with other primary pancreatic neoplasms, especially for specimens from small biopsies and fine needle aspiration (FNA). To improve the diagnosis of this rare pancreatic tumor, we have reported a series of 13 cases of primary pancreatic ES and reviewed the cytopathologic, surgical pathology, clinical, and radiologic features of these neoplasms.

MATERIALS AND METHODS

We performed a retrospective case review of 13 patients with a diagnosis of pancreatic ES from 2 tertiary academic medical centers. A combination of cytology and histopathologic slides were reviewed, and the patient demographics, clinical information, somatic genetics, and radiologic findings were obtained from the electronic medical records.

RESULTS

Five FNA specimens from 5 patients and 8 surgical biopsy or resection specimens were identified and reviewed. The patients included 9 males and 4 females, with a median age of 27 years (range, 15-78 years). The cytology smears were highly cellular and showed a combination of complex tissue fragments and singly dispersed small round blue cells. The final diagnosis was ES for all 5 FNA specimens in accordance with the characteristic cytomorphology, diffuse and/or strong membranous immunolabeling for CD99, membranous β-catenin, and molecular confirmation of EWSR1 using fluorescence in situ hybridization or reverse transcriptase polymerase chain reaction.

CONCLUSIONS

The cytologic diagnosis of ES is challenging, especially in unusual locations such as the pancreas. However, the correct cytologic diagnosis is important because these patients will require neoadjuvant therapy before surgery. Confirmatory molecular studies should be required to render the diagnosis of pancreatic ES.

Metastasis of Ewing Sarcoma to the Pancreas: Case Report and Literature Review

Ewing sarcoma (ES) is a highly aggressive malignant bone cancer. ES is part of the Ewing sarcoma family of tumors (ESFT), which express characteristic t(11;22) translocation as well as higher levels of CD99. Given that metastasis and tumor burden are significant prognostic factors in patient's response to treatment, prompt diagnosis is needed to effectively treat ESFT patients. However, the challenges in classifying and characterizing ESFT complicate effective management and treatment of ES. In this report, we present a rare case of ES metastasis to the pancreas. Upon review of the literature, we found 39 cases of ESFT involving the pancreas, but only 3 were metastatic to the pancreas while the remaining cases of ESFT primarily originated from the pancreas. Given the rarity of such metastasis, the positive outcome in our patient's case may explain the importance of prompt diagnosis in order to initiate appropriate treatment.

Ewing sarcoma and Ewing-like tumors

Ewing sarcoma (ES) and Ewing-like sarcomas are highly aggressive round cell mesenchymal neoplasms, most often occurring in children and young adults. The identification of novel molecular alterations has greatly contributed to a profound reappraisal of classification, to the extent that the category of undifferentiated round cell sarcoma has significantly shrunk. In fact, in addition to Ewing sarcoma, we currently recognize three main categories: round cell sarcomas with EWSR1 gene fusion with non-ETS family members, CIC-rearranged sarcomas, and BCOR-rearranged sarcomas. Interestingly, despite significant morphologic overlap, most of these entities tend to exhibit morphologic features predictive of the underlying molecular alteration. Ewing sarcoma is the prototype of round cell sarcoma whereas in CIC sarcomas, focal pleomorphism and epithelioid morphology can predominate. BCOR sarcomas often exhibit a spindled neoplastic cell population. NFATC2 sarcoma may exhibit remarkable epithelioid features, and PATZ1 sarcomas often feature a sclerotic background. The differential diagnosis for these tumors is rather broad, and among round cell sarcomas includes alveolar rhabdomyosarcoma, desmoplastic small round cell tumor, poorly differentiated round cell synovial sarcoma, small cell osteosarcoma, and mesenchymal chondrosarcoma. A combination of morphologic, immunohistochemical, and molecular findings allows accurate classification in most cases. A granular diagnostic approach to Ewing sarcoma and Ewing-like sarcomas is justified by significant differences in terms of both response to chemotherapy and overall survival. As all these entities are in part defined by specific fusion genes, a molecular diagnostic approach based on NGS technology should be considered. In consideration of the extreme rarity of many of these tumor entities, referral to expert rare cancer centers or to rare cancer networks represents the best strategy in order to minimize diagnostic inaccuracy, and allow proper patient management.