Normal on the Inside: A Case of Recurrent Abdominal Pain, Equivocal CT Appendicitis, and Histologically Normal Appendix in an Adolescent With Chronic Cannabis Use

Cyclic vomiting syndrome (CVS) and cannabinoid hyperemesis syndrome (CHS) are diagnoses of exclusion, and both can anchor clinical thinking in ways that delay recognition of organic pathology.We describe an 18-year-old male patient who attended the emergency department repeatedly between December 2025 and June 2026 with severe abdominal pain and vomiting, against a background of chronic cannabis use.Working diagnoses of CHS and CVS were recorded across multiple admissions.During his March 2026 admission, contrast-enhanced CT of the abdomen and pelvis (CTAP) showed a mildly thickened appendix with smallvolume pelvic free fluid, reported as mild acute appendicitis.Conservative management was commenced but failed to resolve symptoms.Laparoscopic appendicectomy was performed.Intraoperatively, the appendix appeared mildly dilated and injected.Histopathological analysis returned a normal appendix vermiformis with no inflammation, dysplasia, or malignancy.The patient was discharged with resolution of his acute symptoms but re-presented within weeks with identical complaints.At the time of writing, oesophagogastroduodenoscopy and familial Mediterranean fever testing are pending.Faecal calprotectin was 159 microg/g.When CT findings, operative appearances, and histology point in different directions, the underlying diagnosis is not resolved by surgery; it has to be reconsidered from the beginning.