Case Report
Copyright ©The Author(s) 2025. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Jun 15, 2025; 17(6): 106848
Published online Jun 15, 2025. doi: 10.4251/wjgo.v17.i6.106848
Extensive bone metastases from an occult gastric primary: A case report
Chao-Bo Jin, Yong-Sheng Li, Juan Zhang, Jian Wu, Wei-Jing Tao
Chao-Bo Jin, Wei-Jing Tao, Department of Nuclear Medicine, The Affiliated Huaian No. 1 People’s Hospital of Nanjing Medical University, Huai’an 223300, Jiangsu Province, China
Yong-Sheng Li, Department of Rheumatism and Immunology, The Affiliated Huaian No. 1 People’s Hospital of Nanjing Medical University, Huai’an 223300, Jiangsu Province, China
Juan Zhang, Department of Gastroenterology, The Affiliated Huaian No. 1 People’s Hospital of Nanjing Medical University, Huai’an 223300, Jiangsu Province, China
Jian Wu, Department of Pathology, The Affiliated Huaian No. 1 People’s Hospital of Nanjing Medical University, Huai’an 223300, Jiangsu Province, China
Co-first authors: Chao-Bo Jin and Yong-Sheng Li.
Co-corresponding authors: Jian Wu and Wei-Jing Tao.
Author contributions: Jin CB and Li YS collected clinical data and wrote the manuscript, they contributed equally to this article, they are the co-first authors of this manuscript; Zhang J validated clinical interpretations and edited figures; Wu J was responsible for pathology validation and ethics management; Tao WJ was responsible for clinical design and manuscript finalization; Wu J and Tao WJ contributed equally to this article, they are the co-corresponding authors of this manuscript; and all authors thoroughly reviewed and endorsed the final manuscript.
Informed consent statement: Written consent was obtained from the patient’s family to publish this report and any accompanying images.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
Open Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Wei-Jing Tao, MD, Professor, Department of Nuclear Medicine, The Affiliated Huaian No. 1 People’s Hospital of Nanjing Medical University, No. 1 Huanghe West Road, Huaiyin District, Huai’an 223300, Jiangsu Province, China. weijingtao2021@vip.163.com
Received: March 13, 2025
Revised: April 9, 2025
Accepted: May 20, 2025
Published online: June 15, 2025
Processing time: 93 Days and 0.7 Hours
Abstract
BACKGROUND

This report describes a rare case of a small gastric cancer lesion with widespread bone metastases and markedly elevated alkaline phosphatase levels that was initially misdiagnosed as rheumatoid arthritis, as the patient’s sole clinical manifestation was chronic bone pain persisting for 1 year.

CASE SUMMARY

An 83-year-old man was admitted due to worsening generalized joint pain over 1 year. Serum alkaline phosphatase levels were markedly elevated, and technetium-99m methylene diphosphonate single-photon emission computed tomography (CT) and fluorine-18 sodium fluoride positron emission tomography (PET)/CT images showed symmetrical diffuse uptake of the radiotracers throughout the skeleton. Initially, Paget’s disease was suspected, but abnormal hematologic tumor markers and bone biopsy confirmed metastatic adenocarcinoma. Fluorine-18-fluorodeoxyglucose PET/CT did not reveal a primary tumor. The patient had a history of colon polypectomy and tubulovillous adenoma with atypical hyperplasia on pathological examination 10 years prior. Further investigation using gallium-68-labeled fibroblast-activation protein inhibitor PET/CT images showed increased punctate uptake in the gastric antrum. Gastroscopy demonstrated a 1.0 cm ulcerated mass in the prepyloric region, and histopathological evaluation of the biopsy specimen revealed poorly differentiated adenocarcinoma. The incidence of bone metastases from gastric cancer is very low, especially with such extensive involvement.

CONCLUSION

Occult gastric carcinomas with bone metastases necessitate proactive high-risk surveillance and multidisciplinary integration to improve diagnostic accuracy and clinical outcomes.

Keywords: Gastric cancer; Bone metastasis; Fibroblast activation protein inhibitor; Positron emission tomography/computed tomography; Occult primary tumor; Case report

Core Tip: This case highlights an octogenarian with occult gastric cancer manifesting as extensive osteoblastic metastases initially misdiagnosed as rheumatoid arthritis. While fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) failed to detect the primary lesion, gallium-68 fibroblast-activation protein inhibitor PET/CT identified a subtle gastric antral tumor. This underscores the diagnostic utility of fibroblast activation protein inhibitor-targeted PET/CT imaging for gastrointestinal malignancies with low fluorine-18 fluorodeoxyglucose avidity and emphasizes the multidisciplinary integration of tumor markers, advanced imaging, and endoscopic surveillance in high-risk patients to detect clinically silent, aggressive cancers and mitigate diagnostic delays.