Extraosseous Ewing sarcoma with foci of neuroblastoma-like differentiation associated with EWSR1(Ewing sarcoma breakpoint region 1)/FLI1 translocation without prior chemotherapy

Clinicopathological and molecular genetic analysis of 13 cases of primary retroperitoneal Ewing sarcoma

Retroperitoneal Ewing sarcomas (RES) are very rare and mostly described in case reports. The purpose of this study was to retrospectively analyze the clinicopathology, molecular characteristics, biological behavior, and therapeutic information of 13 cases of primary RES with immunohistochemical staining, fluorescence in situ hybridization, RT-PCR and NGS sequencing detection techniques. The thirteen patients included eight males and five females with a mean age of 34 years. Morphologically, the tumors were comprised of small round or epithelial-like cells with vacuolated cytoplasm (6/13,46 %) arranged in diffuse, nested (8/13,62 %) and perivascular (7/13,54 %) patterns. Unusual morphologic patterns, such as meningioma-like swirling structures and sieve-like structures were relatively novel findings. Immunohistochemical studies showed CD99 (12/13; 92 %), CD56 (11/13; 85 %), NKX2.2 (9/13; 69 %), PAX7 (10/11;91 %) and CD117(6/9;67 %) to be positive.12 cases (92 %) demonstrated EWSR1 rearrangement and 3 cases displayed EWSR1::FLI1 fusion by FISH. ERCC4 splice-site variant, a novel pathogenic variant, was discovered for the first time via RNA sequencing. With a median follow-up duration of 14 months (6 to 79 months), 8/13 (62 %) patients died, while 5/13(38 %) survived. Three cases recurred, and five patients developed metastasis to the liver (2 cases), lung (2 cases) and bone (1 case). RES is an aggressive, high-grade tumor, prone to multiple recurrences and metastases, with distinctive morphologic, immunohistochemical, and molecular genetic features. ERCC4 splicing mutation, which is a novel pathogenic variant discovered for the first time, with possible significance for understanding the disease, as well as the development of targeted drugs.

Deep Learning Techniques to Characterize the RPS28P7 Pseudogene and the Metazoa-SRP Gene as Drug Potential Targets in Pancreatic Cancer Patients

The molecular explanation about why some pancreatic cancer (PaCa) patients die early and others die later is poorly understood. This study aimed to discover potential novel markers and drug targets that could be useful to stratify and extend expected survival in prospective early-death patients. We deployed a deep learning algorithm and analyzed the gene copy number, gene expression, and protein expression data of death versus alive PaCa patients from the GDC cohort. The genes with higher relative amplification (copy number >4 times in the dead compared with the alive group) were EWSR1, FLT3, GPC3, HIF1A, HLF, and MEN1. The most highly up-regulated genes (>8.5-fold change) in the death group were RPL30, RPL37, RPS28P7, RPS11, Metazoa_SRP, CAPNS1, FN1, H3-3B, LCN2, and OAZ1. None of their corresponding proteins were up or down-regulated in the death group. The mRNA of the RPS28P7 pseudogene could act as ceRNA sponging the miRNA that was originally directed to the parental gene RPS28. We propose RPS28P7 mRNA as the most druggable target that can be modulated with small molecules or the RNA technology approach. These markers could be added as criteria to patient stratification in future PaCa drug trials, but further validation in the target populations is encouraged.

Deep Learning Techniques to Characterize the RPS28P7 Pseudogene and the Metazoa-SRP Gene as Drug Potential Targets in Pancreatic Cancer Patients

The molecular explanation about why some pancreatic cancer (PaCa) patients die early and others die later is poorly understood. This study aimed to discover potential novel markers and drug targets that could be useful to stratify and extend expected survival in prospective early-death patients. We deployed a deep learning algorithm and analyzed the gene copy number, gene expression, and protein expression data of death versus alive PaCa patients from the GDC cohort. The genes with higher relative amplification (copy number >4 times in the dead compared with the alive group) were EWSR1, FLT3, GPC3, HIF1A, HLF, and MEN1. The most highly up-regulated genes (>8.5-fold change) in the death group were RPL30, RPL37, RPS28P7, RPS11, Metazoa_SRP, CAPNS1, FN1, H3−3B, LCN2, and OAZ1. None of their corresponding proteins were up or down-regulated in the death group. The mRNA of the RPS28P7 pseudogene could act as ceRNA sponging the miRNA that was originally directed to the parental gene RPS28. We propose RPS28P7 mRNA as the most druggable target that can be modulated with small molecules or the RNA technology approach. These markers could be added as criteria to patient stratification in future PaCa drug trials, but further validation in the target populations is encouraged.

Meningeal Ewing Sarcoma/Peripheral PNET: Clinicopathological, Immunohistochemical and FISH study of four cases

Meningeal Ewing Sarcoma (ES)/peripheral primitive neuroectodermal tumor (pPNET) is a rare diagnostically challenging small round cell tumor in the CNS. This study investigates the clinical pathological features of four cases of this tumor from archives of 6 years in our hospital. Patients were within the median age of 21.5 years and male to female ratio was 1:1. The tumors distributed at the supra-tentorial location, posterior fossa and lumbar vertebral canal, usually presenting as the dura-sited nodule or having close connection with the meninges within the cranium or vertebral canal. Histopathologically, small round undifferentiated tumor cells with hypercellularities, scant cytoplasm and inconspicuous nucleoli were observed, although some components such as atypical larger vesicular nuclei, prominent nucleoli of tumor cells, necrotic foci and mesenchymal collagen proliferation forming the lobular structure, were also appreciated. Immunohistochemally, tumor cells displayed membranous positivity of CD99 (4/4), nuclear positivity of FLI-1 (4/4) and NKX2.2 (4/4), negativity of EMA, GFAP and synaptophysin expression. The histochemical PAS staining showed weak positivity in one case. Fluorescence in situ hybridization (FISH) test using EWSR1 (22q12) dual color break apart rearrangement probe showed positive results in two cases. Results suggest that using a panel of immunohistochemical markers, including NKX2.2, CD99, FLI-1, EMA, GFAP and synaptophysin, combined with the supplementary EWSR1 FISH test, helps to define the diagnosis of meningeal ES/pPNET of CNS.

Cervical ganglioneuroma in collision with a metastatic undifferentiated carcinoma

Cervical ganglioneuromas are extremely rare with approximately six case reports. The current report highlights a unique collision tumor between a cervical ganglioneuroma and a metastatic undifferentiated carcinoma arising from a primary gingival mass. A 53-year-old male presented with a 2 cm left gingival mass that was excised and treated with systemic chemotherapy. Consequently, 9 months later, he developed a 3.2 cm left submandibular mass followed by recurrence of the left gingival mass. From the clinicopathologic perspective, this had to be separated from the differentials: ganglioneuroblastoma or metastatic involvement of a lymph node from primary gingival undifferentiated carcinoma.

Ewing sarcoma with extensive neural differentiation: a clinicopathologic, immunohistochemical, and molecular analysis of three cases

OBJECTIVES

Three patients with Ewing sarcomas showing extensive neural differentiation are presented.

METHODS

The patients were two women and one man between the ages of 15 and 35 years. Anatomically, one tumor was in the lung, one in the testis, and one in the cervix uteri. The symptoms were determined by the location of the neoplasm and included respiratory symptoms, testicular pain, and pelvic manifestations, respectively. Complete surgical resection of the tumors was performed.

RESULTS

Histologically, all neoplasms showed similar characteristics-namely, a neoplastic cellular proliferation arranged in sheets and composed of small blue cells with round to oval nuclei and inconspicuous nucleoli typical for Ewing sarcoma. In addition, in two cases, there were areas characterized by the presence of neuropil, ganglion cells, and small cells most compatible with ganglioneuroblastoma, while in one tumor, the neural component was characterized by the presence of small cells with prominent perivascular pseudorosettes more closely resembling ependymoma. Immunohistochemical studies in all cases and molecular analysis in two tumors were in keeping with a diagnosis of Ewing sarcoma.

CONCLUSIONS

The recognition of such histologic variants is important in the diagnostic assessment of these tumors to avoid misinterpretation, especially in small biopsy specimens.

Atypical growth on MRI in a case of Ewing's sarcoma despite lower SUV on PET

Ewing's sarcoma is a rare primary bone malignancy of small round blue cells. Treatment typically consists of neoadjuvant chemotherapy, surgical resection, and adjuvant chemotherapy. The disease response to chemotherapy can be followed with fluorodeoxyglucose (FDG) positron emission tomography (PET), which measures the metabolic activity of the tumor, and by magnetic resonance imaging (MRI), which measures tumor size. We present a unique case in which the tumor grew in size following neoadjuvant chemotherapy but decreased in metabolic activity, making it difficult to judge efficacy of the chemotherapy. An atypical response to chemotherapy in this case caused tumor growth due to a fibrotic reaction while viable tumor cells were eradicated. This case highlights the ability of FDG-PET scan to identify the uncommon situation in which a tumor that increased in size may have had a favorable response to chemotherapy. This possibility should be considered in similar cases in which FDG-PET scan shows diminishing metabolic activity despite tumor growth.