Clinicopathological Presentation of Primary Non-Epithelial Gastrointestinal Tumors: A Retrospective Study from a Tertiary Care Cancer Hospital

Background: Non-epithelial gastrointestinal (GI) tumors are rare, heterogeneous neoplasms of mesenchymal, lymphoid/hematopoietic, or neuroendocrine origin. Limited comprehensive data hinder early diagnosis and optimal management. Methods: A five-year retrospective study was conducted at a tertiary care cancer hodpital, included histopathologically confirmed primary non-epithelial GI tumors; epithelial tumors were excluded. Demographic, clinical, anatomical, morphological, and immunohistochemical data were reviewed. Results: Of 66 patients, gastrointestinal stromal tumor (GIST) was most common (34.8%), followed by primary GI melanoma (30.3%) and non-Hodgkin lymphoma (NHL) (27.2%). Rare types included liposarcoma, malignant peripheral nerve sheath tumor, plasmacytoma, ganglioneuroma, and lipoma (each 1.51%). Most patients were 41–60 years old (57.5%); males predominated (M:F = 39:27), especially in melanoma and NHL. The anorectum (36.3%) was the most frequent site, mainly due to melanoma, followed by the stomach (30.3%) and small intestine. GISTs occurred more often in the small intestine than the stomach, opposite to global trends. Histopathology and immunohistochemistry were essential for accurate diagnosis, especially for rare tumors. Conclusions: GIST, melanoma, and NHL predominate among non-epithelial GI tumors, mainly affecting middle-aged to elderly adults. The high frequency of anorectal melanoma and small-intestinal GIST suggests regional or referral influences and underscores the need for thorough small bowel evaluation. Rare tumors require meticulous pathological workup to avoid misdiagnosis. Multicenter and molecular studies are needed to refine epidemiologic understanding and improve outcomes.