Purpose: Neuroendocrine tumors (NET) commonly involve the gastrointestinal system, particularly the small intestine, appendix and pancreas. These tumors can result in ectopic production of Adrenocorticotropic hormone (ACTH). Mesenteric NETs are extremely rare and often secondary to another primary tumor. Our aim is to discuss a case and literature review to raise awareness about this rare condition. Method: We report a case of a primary small bowel mesenteric ACTH secreting NET. Ethics approval was gained, the patient’s electronic medical records were accessed and intraoperative images taken of the mass. A literature review was conducted and extensive search of electronic databases including Medline, Scopus, Embase, Cochrane and PubMed was performed. Results: A 68-year-old female was found to have ectopic Cushing’s syndrome due to excessive ACTH secretion from small bowel primary lesions and mesenteric metastasis. Initially, only the mesenteric mass was detected on imaging and endoscopy/colonoscopy, and it was only with surgical exploration that the small bowel lesions were found. This highlights the importance of high clinical suspicion and robust investigation when locating NETs. Surgical resection of the affected small bowel and mesentery was the definitive treatment for this patient. Initial hydrocortisone replacement therapy was needed, and subsequent biochemical tests and clinical reviews demonstrated no recurrence. Conclusion: Primary mesenteric NETs are extremely rare with only a few cases reported globally; thus, robust investigations and surgical exploration as both a diagnostic and therapeutic procedure must be considered when searching for lesions.