Case Report: Gastric submucosal neoplasm with CTNNB1 mutation showing GLI1 overexpression and epithelial differentiation

New disease entities have been emerging based on molecular pathological findings, such as pseudoendocrine sarcoma and mesenchymal neoplasm with GLI1 gene alterations, which resemble well-differentiated neuroendocrine tumors. We report a unique case of a gastric submucosal neoplasm of approximately 1...

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Main Authors: Karin Ashizawa, Tsuyoshi Saito, Yukinori Yube, Shinji Mine, Tetsu Fukunaga, Cristina R. Antonescu, Takashi Yao
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-04-01
Series:Frontiers in Medicine
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Online Access:https://www.frontiersin.org/articles/10.3389/fmed.2025.1526614/full
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author Karin Ashizawa
Tsuyoshi Saito
Tsuyoshi Saito
Yukinori Yube
Shinji Mine
Tetsu Fukunaga
Cristina R. Antonescu
Takashi Yao
author_facet Karin Ashizawa
Tsuyoshi Saito
Tsuyoshi Saito
Yukinori Yube
Shinji Mine
Tetsu Fukunaga
Cristina R. Antonescu
Takashi Yao
author_sort Karin Ashizawa
collection DOAJ
description New disease entities have been emerging based on molecular pathological findings, such as pseudoendocrine sarcoma and mesenchymal neoplasm with GLI1 gene alterations, which resemble well-differentiated neuroendocrine tumors. We report a unique case of a gastric submucosal neoplasm of approximately 1.5 cm in size with CTNNB1 mutation showing GLI1 overexpression and epithelial differentiation in a 66-year-old man. It was incidentally identified by routine health screening, and was a slowly growing tumor. Macroscopically, it was a slightly protruded tumor into the mucosa, and was primarily located from the submucosa to the muscularis propria. It was a well-defined lesion measured approximately 20 mm, and was almost stable during almost 5 years after initial identification of the tumor. Uniform round-to-epithelioid cells arranged in solid trabeculae with a microtubular/acinar appearance were seen microscopically. Occasional mitotic figures were noted, but no necrosis was observed. Immunohistochemistry (IHC) demonstrated diffuse expression of pan-cytokeratin, CD10, and CD56 without neuroendocrine markers (chromogranin A, synaptophysin, and INSM1). Molecular analysis confirmed the presence of a hot spot CTNNB1 mutation (S33C), supported by diffuse β-catenin nuclear expression by IHC. Further molecular investigations revealed the absence of GLI1 gene rearrangements, GLI1 amplification, and other fusions. Several differential diagnoses were considered; however, none adequately fit the criteria. The patient remained disease-free for 24 months postoperatively without further adjuvant therapy.
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spelling doaj-art-00d839be22bb4384a1ef46b6688f719d2025-08-20T01:55:12ZengFrontiers Media S.A.Frontiers in Medicine2296-858X2025-04-011210.3389/fmed.2025.15266141526614Case Report: Gastric submucosal neoplasm with CTNNB1 mutation showing GLI1 overexpression and epithelial differentiationKarin Ashizawa0Tsuyoshi Saito1Tsuyoshi Saito2Yukinori Yube3Shinji Mine4Tetsu Fukunaga5Cristina R. Antonescu6Takashi Yao7Department of Human Pathology, Graduate School of Medicine, Juntendo University, Bunkyo-ku, JapanDepartment of Human Pathology, Graduate School of Medicine, Juntendo University, Bunkyo-ku, JapanIntractable Disease Research Center, Graduate School of Medicine, Juntendo University, Bunkyo-ku, JapanDepartment of Upper Gastroenterological Surgery, Juntendo University Hospital, Bunkyo-ku, JapanDepartment of Upper Gastroenterological Surgery, Juntendo University Hospital, Bunkyo-ku, JapanDepartment of Upper Gastroenterological Surgery, Juntendo University Hospital, Bunkyo-ku, JapanDepartment of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, United StatesDepartment of Human Pathology, Graduate School of Medicine, Juntendo University, Bunkyo-ku, JapanNew disease entities have been emerging based on molecular pathological findings, such as pseudoendocrine sarcoma and mesenchymal neoplasm with GLI1 gene alterations, which resemble well-differentiated neuroendocrine tumors. We report a unique case of a gastric submucosal neoplasm of approximately 1.5 cm in size with CTNNB1 mutation showing GLI1 overexpression and epithelial differentiation in a 66-year-old man. It was incidentally identified by routine health screening, and was a slowly growing tumor. Macroscopically, it was a slightly protruded tumor into the mucosa, and was primarily located from the submucosa to the muscularis propria. It was a well-defined lesion measured approximately 20 mm, and was almost stable during almost 5 years after initial identification of the tumor. Uniform round-to-epithelioid cells arranged in solid trabeculae with a microtubular/acinar appearance were seen microscopically. Occasional mitotic figures were noted, but no necrosis was observed. Immunohistochemistry (IHC) demonstrated diffuse expression of pan-cytokeratin, CD10, and CD56 without neuroendocrine markers (chromogranin A, synaptophysin, and INSM1). Molecular analysis confirmed the presence of a hot spot CTNNB1 mutation (S33C), supported by diffuse β-catenin nuclear expression by IHC. Further molecular investigations revealed the absence of GLI1 gene rearrangements, GLI1 amplification, and other fusions. Several differential diagnoses were considered; however, none adequately fit the criteria. The patient remained disease-free for 24 months postoperatively without further adjuvant therapy.https://www.frontiersin.org/articles/10.3389/fmed.2025.1526614/fullpseudoendocrine sarcomastomachCTNNB1cytokeratinepithelialneuroendocrine
spellingShingle Karin Ashizawa
Tsuyoshi Saito
Tsuyoshi Saito
Yukinori Yube
Shinji Mine
Tetsu Fukunaga
Cristina R. Antonescu
Takashi Yao
Case Report: Gastric submucosal neoplasm with CTNNB1 mutation showing GLI1 overexpression and epithelial differentiation
Frontiers in Medicine
pseudoendocrine sarcoma
stomach
CTNNB1
cytokeratin
epithelial
neuroendocrine
title Case Report: Gastric submucosal neoplasm with CTNNB1 mutation showing GLI1 overexpression and epithelial differentiation
title_full Case Report: Gastric submucosal neoplasm with CTNNB1 mutation showing GLI1 overexpression and epithelial differentiation
title_fullStr Case Report: Gastric submucosal neoplasm with CTNNB1 mutation showing GLI1 overexpression and epithelial differentiation
title_full_unstemmed Case Report: Gastric submucosal neoplasm with CTNNB1 mutation showing GLI1 overexpression and epithelial differentiation
title_short Case Report: Gastric submucosal neoplasm with CTNNB1 mutation showing GLI1 overexpression and epithelial differentiation
title_sort case report gastric submucosal neoplasm with ctnnb1 mutation showing gli1 overexpression and epithelial differentiation
topic pseudoendocrine sarcoma
stomach
CTNNB1
cytokeratin
epithelial
neuroendocrine
url https://www.frontiersin.org/articles/10.3389/fmed.2025.1526614/full
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