Malignant Gastrointestinal Neuroectodermal Tumor: Clinicopathologic, Immunohistochemical, and Molecular Analysis of 19 Cases

Am J Surg Pathol. 2020 Apr;44(4):456-466. doi: 10.1097/PAS.0000000000001396.

Abstract

A malignant gastrointestinal neuroectodermal tumor (GNET) is rare, and it is therefore yet to be completely understood. This study aimed to present the clinicopathologic features of GNET, including treatment information. We included 19 patients with GNET with a mean tumor size of 4.2 cm. The most common site of tumor origin was the small intestine (57.9%), followed by the stomach (15.8%), colon (10.5%), ileocecal junction (5.3%), lower esophagus (5.3%), and anal canal (5.3%). Microscopically, the tumors were composed of epithelioid cells with eosinophilic or clear cytoplasm arranged in nest, sheet-like, papillary, or pseudoalveolar patterns and/or spindle tumor cells with eosinophilic cytoplasm arranged in a fascicular pattern. Immunohistochemically, the tumor cells stained positively for S100 (19/19,100%), SOX10 (14/15, 93.3%), vimentin (17/17, 100%), synaptophysin (Syn) (7/17, 41.2%), CD56 (4/13, 30.8%), CD99 (1/5, 20%), and CD117 (1/15, 6.7%), and negatively for HMB45, Melan A, DOG1, CD34, AE1/AE3, CAM5.2, chromogranin A, smooth muscle actin, and desmin. In total, 14/15 (93.3%) cases showed split Ewing sarcoma breakpoint region 1 gene (EWSR1) signals consistent with a chromosomal translocation involving EWSR1. Within a mean follow-up of 29.7 months (range: 3 to 63 mo), 2/15 (13.3%) patients died of disease, 5 (33.3%) were alive with disease, and 8 (53.3%) had no evidence of disease. Two and 1 patients showed partial response to apatinib and anlotinib, respectively. In conclusion, GNET has distinctive morphologic, immunohistochemical, and molecular genetic features and should be distinguished from other gastrointestinal tract malignancies. Apatinib and anlotinib might be effective for the treatment of advanced GNET and could prolong patient survival.

MeSH terms

  • Adult
  • Antineoplastic Agents / therapeutic use
  • Biomarkers, Tumor* / analysis
  • Biomarkers, Tumor* / genetics
  • Female
  • Gastrointestinal Neoplasms* / chemistry
  • Gastrointestinal Neoplasms* / drug therapy
  • Gastrointestinal Neoplasms* / genetics
  • Gastrointestinal Neoplasms* / pathology
  • Genetic Predisposition to Disease
  • Humans
  • Immunohistochemistry*
  • In Situ Hybridization, Fluorescence*
  • Indoles / therapeutic use
  • Male
  • Middle Aged
  • Neuroectodermal Tumors* / chemistry
  • Neuroectodermal Tumors* / drug therapy
  • Neuroectodermal Tumors* / genetics
  • Neuroectodermal Tumors* / pathology
  • Predictive Value of Tests
  • Protein Kinase Inhibitors / therapeutic use
  • Pyridines / therapeutic use
  • Quinolines / therapeutic use
  • RNA-Binding Protein EWS / genetics*
  • Translocation, Genetic*
  • Treatment Outcome
  • Tumor Burden

Substances

  • Antineoplastic Agents
  • Biomarkers, Tumor
  • EWSR1 protein, human
  • Indoles
  • Protein Kinase Inhibitors
  • Pyridines
  • Quinolines
  • RNA-Binding Protein EWS
  • anlotinib
  • apatinib