AUTHOR=Zhang Zhiqiang , Zhang Junfeng , Chen Peng , Kou Xuexia , Lan Yunsheng , Jia Yingdong 

TITLE=A collision tumor composed of colon adenocarcinoma and large cell neuroendocrine carcinoma with gingival metastasis: a case report

JOURNAL=Frontiers in Oncology

VOLUME=Volume 15 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2025.1633770

DOI=10.3389/fonc.2025.1633770

ISSN=2234-943X

ABSTRACT=Collision tumors represent a relatively uncommon form of tumor manifestation, characterized by the independent coexistence of multiple distinct types of tumors. Large cell neuroendocrine carcinoma of the colorectum is a rare entity, with limited reports describing collision tumors involving adenocarcinoma and large cell neuroendocrine carcinoma. Distant metastases of colorectal cancer typically occur in sites such as bone, liver, and lungs; however, metastasis to the gingiva is rarely encountered. This paper reports a case of a collision tumor comprising colonic adenocarcinoma and large cell neuroendocrine carcinoma, with accompanying gingival metastasis.