title: Primitive Neuroectodermal Tumor of the Stomach: A Case Report.
abstract: Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET) is a highly aggressive small round cell tumor that mainly occurs in the bone or soft tissue of children or young adults but is extremely rare in the stomach. A 55-year-old man presented with melena and anemia. On endoscopy, an ulcerofungating mass was observed in the high body and total gastrectomy was performed. Histologically, the mass consisted of small round cells with scanty cytoplasm and inconspicuous nucleoli. They often formed perivascular pseudorosettes and multinucleated giant cells were frequently observed. The tumor cells strongly expressed CD99, FLI1, and chromogranin and weakly expressed synaptophysin and CD56. EWS-FLI1 fusion transcript was confirmed by reverse transcription-polymerase chain reaction. ES/PNET is frequently misdiagnosed because of its similarity with small cell carcinoma. Although gastric ES/PNET is very rare, it should be included in differential diagnoses of small round cell tumor in the stomach.
authors.affiliation: University of Ulsan Collage of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Min Jeong
authors.initials: MJ
authors.lastname: Song
authors.affiliation: University of Ulsan Collage of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Soyeon
authors.initials: S
authors.lastname: An
authors.affiliation: University of Ulsan Collage of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Seung Soo
authors.initials: SS
authors.lastname: Lee
authors.affiliation: University of Ulsan Collage of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Beom Su
authors.initials: BS
authors.lastname: Kim
authors.affiliation: University of Ulsan Collage of Medicine, Asan Medical Center, Seoul, Republic of Korea jihunkim@amc.seoul.kr.
authors.forename: Jihun
authors.initials: J
authors.lastname: Kim
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D018242:Neuroectodermal Tumors, Primitive / Q000235:genetics / Q000473:pathology*; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D051789:Proto-Oncogene Protein c-fli-1 / Q000235:genetics; D034802:RNA-Binding Protein EWS / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; C106031:EWS-FLI fusion protein; D015514:Oncogene Proteins, Fusion; D051789:Proto-Oncogene Protein c-fli-1; D034802:RNA-Binding Protein EWS
keywords: EWS-FLI1; Ewing sarcoma; primitive neuroectodermal tumor; stomach neoplasms