Malignant gastrointestinal neuroectodermal tumor with BRAF mutation and a history of malignant melanoma: A case report

Small Intestine Gastrointestinal Clear Cell Sarcoma: A Case Report and Review of the Literature

Gastrointestinal clear cell sarcoma (GICCS)/malignant gastrointestinal neuroectodermal tumor (GNET) is an extremely rare form of cancer with aggressive clinical behavior. It has distinct pathological, immunohistochemical, ultrastructural, and molecular features. Herein, we present the case of a 20-year-old woman with no notable medical history who presented to the outpatient department with complaints of abdominal pain and vomiting. Symptoms had been evolving for 3 months. The physical examination revealed slight abdominal tenderness and melena. Biological investigations revealed iron-deficiency anemia. The upper and lower endoscopies showed no abnormalities. Magnetic resonance enterography revealed small bowel wall thickening of 15 mm × 2 mm. Exploratory laparotomy revealed an ileal mass with mesenteric lymphadenopathy. A wide resection of the mass was then performed. The final pathological report confirmed the diagnosis of small bowel GICCS/GNET. After 11 months of follow-up, the patient presented with mesenteric lymph node metastases.

Malignant gastrointestinal neuroectodermal tumor: a case report and literature review

Introduction and importance

A malignant gastrointestinal neuroectodermal tumor (GNET) is an extremely rare primary malignant mesenchymal tumor of the gastrointestinal tract characterized by EWSR1 gene rearrangement. An optimal systemic treatment strategy for advanced/recurrent GNET has not yet been identified.

Case presentation

A 24-year-old male patient was hospitalized with abdominal pain and underwent two operations for a tumor in his small intestine. Immunohistochemistry (IHC) showed strong expression of S-100 protein and SOX 10. Fluorescence in situ hybridization analysis and next-generation sequencing analysis indicated that there were EWSR gene rearrangements and the presence of EWSR-ATP1 gene fusions, respectively. The diagnosis of GNET in the small intestine was confirmed by pathology. The young patient received the fifth-line of apatinib mesylate and the sixth-line of apatinib combined with temozolomide. The two apatinib-containing regimens showed stable disease and progression-free survival of 4.7 months and 3.1 months with single-agent apatinib or apatinib combined with temozolomide, respectively.

Clinical discussion

To our best knowledge, this is the first report of malignant GNET treated with apatinib and temozolomide. Apatinib-containing regimens might has antineoplastic activity against GNET. The authors reviewed the relevant reports of previous GNET treatment, summarized the clinicopathological characteristics of GNET, and found that there are no reports of apatinib for backline treatment of GNET.

Conclusion

Containing apatinib may provide an additional treatment option for patients with chemotherapy-resistant GNET tumors.

A Case Series of Metastatic Malignant Gastrointestinal Neuroectodermal Tumors and Comprehensive Genomic Profiling Analysis of 20 Cases

Malignant gastrointestinal neuroectodermal tumor (GNET) is an ultra-rare soft tissue sarcoma, therefore often misdiagnosed and has no available standard treatment. Here, we report 3 cases of metastatic GNET with variable clinical courses. Our small case series as well as extensive literature review, further support that GNET is a spectrum of diseases with variable inherent biology and prognosis. Surgical management in the setting of recurrent/metastatic disease may be appropriate for GNET with indolent nature. Response to systemic treatments including chemotherapy and targeted treatments is variable, likely related to heterogenous biology as well. Furthermore, we retrospectively identified 20 additional GNET cases from Foundation Medicine’s genomic database and expanded on their clinicopathological and genomic features. Comprehensive genomic profiling (CGP) with DNA and RNA sequencing of this cohort, in the course of clinical care, demonstrated recurrent EWSR1 chromosomal rearrangements and a sparsity of additional recurrent or driver genomic alterations. All cases had low tumor mutational burden (TMB) and were microsatellite stable.

Synchronous Malignant Gastrointestinal Neuroectodermal Tumor and SMARCA4-Deficient Undifferentiated Carcinoma With Independent Origins in the Small Intestine: A Case Report

Background

Malignant gastrointestinal neuroectodermal tumor (GNET) is a rare malignant mesenchymal neoplasm that commonly arises in the small bowel, stomach or colon. Meanwhile, SMARCA4-deficient undifferentiated carcinoma is a rarely reported entity with highly aggressive behavior that may involve the ovary, lung, gastrointestinal (GI) tract, endometrium and other organs. To our knowledge, we describe for the first time, an extremely rare case of synchronous GNET and SMARCA4-deficient undifferentiated carcinoma with independent origins in the small intestine.

Case Presentation

A 46-year-old woman presented with multiple small intestine masses and underwent surgical resection. Two distinct entities, GNET and SMARCA4-deficient undifferentiated carcinoma, were identified. GNET was composed of epithelioid and spindle cells with clear or eosinophilic cytoplasm arranged in sheets, nest, papillary, fascicular, palisade, rosette like or pseudoalveolar pattern. The neoplastic cells were positive for S-100 and SOX-10. Ewing sarcoma breakpoint region 1 gene (EWSR1) rearrangement was confirmed by fluorescence in situ hybridization (FISH), and EWSR1-CREB1 fusion was revealed by next-generation sequencing (NGS). SMARCA4-deficient undifferentiated carcinoma was composed mainly of poorly adhesive rhabdoid cells with eosinophilic cytoplasm arranged in a diffuse pattern. Multifocal necrosis, brisk mitotic figures as well as multinucleated tumor cells were observed. The neoplastic cells diffusely expressed pancytokeratin and vimentin, and was negative for SMARCA4(BRG1). Frame shift mutation of SMARCA4 was detected by NGS.

Conclusions

This is the first report that GNET and SMARCA4-deficient undifferentiated carcinoma occurred simultaneously in the small intestine, with the latter showing multiple involvement of the jejunum and ileum. The potential mechanism underlying co-existence of these two rare malignancies is unknown and need further investigations and concern.