Histology-Proven Gastrointestinal Metastasis from Nongastrointestinal Malignancies: Experience of This Rare Occurrence in a Single Center

Abstract

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.