KAPOSI SARCOMA IN PATIENTS WITH INFLAMMATORY BOWEL DISEASE: A SYSTEMATIC REVIEW

Abstract INTRODUCTION Kaposi sarcoma is a rare vascular malignancy of the endothelial cells caused by human herpesvirus-8 (HHV-8) which typically affects the skin, but may also involve the lymph nodes, mucosa, or viscera. Kaposi sarcoma often initially presents as non-pruritic violet papules on the skin and mucosa which may disseminate to other organs, including those of the gastrointestinal and respiratory tracts. While Kaposi sarcoma is considered to be an AIDS-defining illness, it can also be seen in patients on long-term immunosuppression, such as in patients with inflammatory bowel disease (IBD). METHODS A systematic literature search was conducted using PubMed, Scopus, and ScienceDirect to retrieve studies from inception up to September 2025. Studies describing patients with inflammatory bowel disease and Kaposi sarcoma were included. According to PRISMA guidelines, two reviewers completed the initial title and abstract screening, full text review, and data extraction. A total of 39 papers were included in the study. RESULTS Among the included studies, the age range of cases of Kaposi sarcoma in patients with IBD ranged from 21-85. Kaposi sarcoma was more commonly seen in patients with ulcerative colitis (69.2% of cases), followed by Crohn’s disease (28.2%), and unspecified IBD (2.6%). Kaposi sarcoma was located in the colon/rectum in 55.3% of cases, followed by skin (44.7%), small bowel (34.2%), and less frequently in the esophagus and duodenum (2.6%). 17.9% of patients were HIV-positive. Among cases in which HHV-8 was tested, the virus was detected in Kaposi sarcoma lesions in 100% of cases. The most common immunosuppressive drugs included corticosteroids (65.0% of cases), azathioprine (25.0%), infliximab (22.5%), and vedolizumab (12.5%). Both short-term and long-term immunosuppression were associated with Kaposi sarcoma in the included studies with cases emerging after less than a month of immunosuppression, while other cases occurred after a decade of immunosuppression. While the vast majority of cases of Kaposi sarcoma occurred in patients on immunosuppressive therapy, two cases occurred in patients not on immunosuppression and without HIV, hinting at a possible complication of the disease process of IBD. CONCLUSION Kaposi sarcoma can rarely present in patients with inflammatory bowel disease, especially those on immunosuppressive therapy. Kaposi sarcoma may have overlapping symptoms with inflammatory bowel disease, such as abdominal pain, diarrhea, hemorrhage, and bowel obstruction, making diagnosis difficult. Increased awareness of Kaposi sarcoma as a rare complication of IBD, especially for patients on immunosuppressive therapy, can allow for early diagnosis and prevent delays in management.