Background <p>Mesenteric cysts are rare benign intra-abdominal lesions, most often arising in the small bowel mesentery. Herniation of a mesenteric cyst is exceptionally uncommon and has been reported only within inguinal hernias. We present the first documented case of a mesenteric cyst incarcerated within a primary paraumbilical ventral hernia.</p> Case Presentation <p>A 58-year-old male presented with a progressively enlarging abdominal swelling and discomfort for three years. Clinical and operative findings revealed a large mesenteric cyst incarcerated within a primary paraumbilical ventral hernia. The patient underwent cyst excision and onlay mesh hernioplasty. Histopathology confirmed a unilocular mesenteric cyst lined by flattened epithelium with fibrous tissue and scattered smooth muscle fibers. The postoperative course was uneventful, and the patient remains recurrence-free at 24 months of follow-up.</p> Conclusion <p>This case highlights a uniquely rare presentation of a mesenteric cyst. The literature review revealed only three previously published reports of mesenteric cysts herniating into the abdominal wall, all of which were associated with inguinal hernias. Awareness of this diagnostic possibility is important to guide appropriate surgical planning. Complete excision with hernia repair is associated with excellent outcomes, as demonstrated in this case.</p>