AUTHOR=Zhao Xin-Yu , Li Chun-Qiang , Zhang Shi-Yao , Liu Gang 

TITLE=Case Report: An Unusual Case of Pulmonary Metastatic Adenocarcinoma From Low-Grade Appendiceal Mucinous Neoplasms

JOURNAL=Frontiers in Oncology

VOLUME=Volume 12 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2022.906344

DOI=10.3389/fonc.2022.906344

ISSN=2234-943X

ABSTRACT=Background: Low-grade appendiceal mucinous neoplasms (LAMNs) are indolent tumors with low-grade cytology. Although peritoneal dissemination is common due to tumor rupture and mucinous deposits on the visceral peritoneal surface, distant involvement, such as lung, is rarely seen due to lack of invasiveness.
Case Presentation: A 70-year-old woman presented to hospital due to continuously elevated CEA levels for 10 months without any symptoms. Positron emission tomography/computed tomography (PET/CT) revealed two lesions located in the left lung and appendix. The postoperative pathology results revealed pulmonary mucinous adenocarcinoma and low-grade appendiceal mucinous neoplasm (LAMN). Then we performed the next generation sequencing (NGS) to clarify the relationship between two tumors. The sequencing result showed that both tumors harbored the common tumor mutations, KRAS (p.G12D), GNAS (p.R201H), and BRAF (p.R735Q), which indicated that the pulmonary tumor was a metastasis of LAMN.
Conclusion: This case is unusual in that the primary LAMN and the pulmonary metastasis is present at the time of diagnosis. This study reported the first pulmonary metastasis from LAMN verified by NGS.