Introduction Lymph nodes, lung, liver, bone, and brain are the commonest metastatic sites for malignancies arising in various body sites. Gastrointestinal (GI) tract is a very uncommon metastatic site and the present study describes the single-center experience of GI metastases from non-GI malignancies.

Aims and Objectives To study the spectrum of metastatic tumors to GI tract and elucidate their clinicopathological characteristics.

Materials and Methods This was a retrospective study done on cases diagnosed from 2015 to 2023 at our institute. All cases of non-GI malignancies metastatic to hollow GI tract were included. Cases with GI primary, hematological malignancies, cases with exclusive serosal deposits, and direct invasion of a GI organ from an adjacent primary tumor were excluded. Apart from hematoxylin & eosin (H&E)-stained slides, immunohistochemistry findings of these were reviewed.

Results Thirty-six patients were histologically proven GI metastases from non-GI malignancies diagnosed during the study period. Most cases were seen in 5th to 7th decade with a significant female preponderance (M:F of 1:8). The commonest metastatic GI sites were small bowel (n = 11), sigmoid colon (n = 9), and rectum (n = 7), followed by stomach (n = 3), appendix (n = 3), gall bladder (n = 2), and ampulla (n = 1). Stricture, perforation, and nodular mucosa were the most common endoscopic findings. The most common primary malignancies in females were ovarian serous carcinoma (n =21) followed by squamous cell carcinoma (SCC) of cervix (n = 8). In males, there was no site preference, and the primary sites included prostate, lung, kidney, and oral mucosa.

Conclusion The study highlights the rare occurrence of GI metastases from non-GI malignancies. Females are at greater risk of such metastases primarily from ovarian serous carcinoma and cervical SCCs.

N.V. and S.G.U. were involved in the conceptualization and design of the study, defining its intellectual content, conducting literature searches, and acquiring and analyzing data. They also performed statistical analyses, prepared and edited the manuscript, and contributed to its review, serving as guarantors for the work. S.G. assisted with data acquisition, analysis, and manuscript preparation. M.S.U. and T.R.P. also focused on the conceptual and design aspects, as well as data acquisition and analysis. Collectively, the authors ensured a comprehensive approach to the research and manuscript development.

The study was approved by the NIMS Institutional Ethics Committee with approval number EC/NIMS/3446/2024 dated 11.05.2024. The procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional) and with the Helinski Declaration of 1964, as reviewed in 2013. Consent waiver form was obtained from the Ethics Committee due to the retrospective nature of the study.

Received: 27 July 2024

Accepted: 21 September 2024

Article published online:
22 October 2024

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