Long-term remission of microsatellite instability-high adenosquamous carcinoma in gastric antrum: a case report

BackgroundGastric adenosquamous carcinoma (ASC) is an exceedingly rare neoplasm. Its infrequent occurrence has resulted in sparse literature on its diagnosis and management, presenting considerable challenges for clinical practice.Case presentationA 70-year-old male presented with epigastric pain an...

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Main Authors: Peng Zhang, Jing Yang, Yongyong Liu, Qing Zhou, Caiqiang Xue, Bin Zhang, Yumin Li
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-04-01
Series:Frontiers in Oncology
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Online Access:https://www.frontiersin.org/articles/10.3389/fonc.2025.1516966/full
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author Peng Zhang
Jing Yang
Yongyong Liu
Qing Zhou
Caiqiang Xue
Bin Zhang
Yumin Li
author_facet Peng Zhang
Jing Yang
Yongyong Liu
Qing Zhou
Caiqiang Xue
Bin Zhang
Yumin Li
author_sort Peng Zhang
collection DOAJ
description BackgroundGastric adenosquamous carcinoma (ASC) is an exceedingly rare neoplasm. Its infrequent occurrence has resulted in sparse literature on its diagnosis and management, presenting considerable challenges for clinical practice.Case presentationA 70-year-old male presented with epigastric pain and, upon gastroscopy and CT imaging, was found to have a mass in the gastric antrum. Histopathological analysis confirmed the diagnosis of adenosquamous carcinoma. Immunohistochemical staining revealed a loss of PMS2 and MLH-1 expression, while molecular analysis confirmed MLH-1 methylation, suggesting a microsatellite instability-high (MSI-H) phenotype. The PD-L1 combined positive score (CPS) was remarkably elevated at 80. Postoperatively, the patient received six cycles of oxaliplatin in conjunction with PD-1 inhibitor therapy. At the one-year follow-up, the patient remained in long-term remission, with no evidence of recurrence.ConclusionThis case underscores the potential efficacy of integrating surgery, chemotherapy, and immunotherapy in managing gastric ASC, particularly in the context of MSI-H and elevated PD-L1 expression. It further emphasizes the critical role of comprehensive molecular profiling in guiding personalized therapeutic strategies for such rare malignancies. Further research and additional case reports are imperative to establish optimal management protocols for gastric ASC and to enhance long-term outcomes.
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spelling doaj-art-d2cf0392ef7849c895e7f26125d711fa2025-08-20T02:16:39ZengFrontiers Media S.A.Frontiers in Oncology2234-943X2025-04-011510.3389/fonc.2025.15169661516966Long-term remission of microsatellite instability-high adenosquamous carcinoma in gastric antrum: a case reportPeng Zhang0Jing Yang1Yongyong Liu2Qing Zhou3Caiqiang Xue4Bin Zhang5Yumin Li6Department of Pathology, Lanzhou University Second Hospital, Lanzhou, Gansu, ChinaDepartment of Pathology, Chengdu Integrated Traditional Chinese Medicine (TCM) and Western Medicine Hospital, Chengdu, Sichuan, ChinaDepartment of General Surgery, Lanzhou University Second Hospital, Lanzhou, Gansu, ChinaDepartment of Radiology, Lanzhou University Second Hospital, Lanzhou, Gansu, ChinaDepartment of Radiology, Lanzhou University Second Hospital, Lanzhou, Gansu, ChinaDepartment of Radiology, Lanzhou University Second Hospital, Lanzhou, Gansu, ChinaGansu Province Key Laboratory of Environmental Oncology, Lanzhou University Second Hospital, Lanzhou, Gansu, ChinaBackgroundGastric adenosquamous carcinoma (ASC) is an exceedingly rare neoplasm. Its infrequent occurrence has resulted in sparse literature on its diagnosis and management, presenting considerable challenges for clinical practice.Case presentationA 70-year-old male presented with epigastric pain and, upon gastroscopy and CT imaging, was found to have a mass in the gastric antrum. Histopathological analysis confirmed the diagnosis of adenosquamous carcinoma. Immunohistochemical staining revealed a loss of PMS2 and MLH-1 expression, while molecular analysis confirmed MLH-1 methylation, suggesting a microsatellite instability-high (MSI-H) phenotype. The PD-L1 combined positive score (CPS) was remarkably elevated at 80. Postoperatively, the patient received six cycles of oxaliplatin in conjunction with PD-1 inhibitor therapy. At the one-year follow-up, the patient remained in long-term remission, with no evidence of recurrence.ConclusionThis case underscores the potential efficacy of integrating surgery, chemotherapy, and immunotherapy in managing gastric ASC, particularly in the context of MSI-H and elevated PD-L1 expression. It further emphasizes the critical role of comprehensive molecular profiling in guiding personalized therapeutic strategies for such rare malignancies. Further research and additional case reports are imperative to establish optimal management protocols for gastric ASC and to enhance long-term outcomes.https://www.frontiersin.org/articles/10.3389/fonc.2025.1516966/fulllong-term remissionmicrosatellite instability-highadenosquamous carcinomagastric antrumcase report
spellingShingle Peng Zhang
Jing Yang
Yongyong Liu
Qing Zhou
Caiqiang Xue
Bin Zhang
Yumin Li
Long-term remission of microsatellite instability-high adenosquamous carcinoma in gastric antrum: a case report
Frontiers in Oncology
long-term remission
microsatellite instability-high
adenosquamous carcinoma
gastric antrum
case report
title Long-term remission of microsatellite instability-high adenosquamous carcinoma in gastric antrum: a case report
title_full Long-term remission of microsatellite instability-high adenosquamous carcinoma in gastric antrum: a case report
title_fullStr Long-term remission of microsatellite instability-high adenosquamous carcinoma in gastric antrum: a case report
title_full_unstemmed Long-term remission of microsatellite instability-high adenosquamous carcinoma in gastric antrum: a case report
title_short Long-term remission of microsatellite instability-high adenosquamous carcinoma in gastric antrum: a case report
title_sort long term remission of microsatellite instability high adenosquamous carcinoma in gastric antrum a case report
topic long-term remission
microsatellite instability-high
adenosquamous carcinoma
gastric antrum
case report
url https://www.frontiersin.org/articles/10.3389/fonc.2025.1516966/full
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AT yongyongliu longtermremissionofmicrosatelliteinstabilityhighadenosquamouscarcinomaingastricantrumacasereport
AT qingzhou longtermremissionofmicrosatelliteinstabilityhighadenosquamouscarcinomaingastricantrumacasereport
AT caiqiangxue longtermremissionofmicrosatelliteinstabilityhighadenosquamouscarcinomaingastricantrumacasereport
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