Goblet cell carcinoid of the appendix: Six case reports.

Background: Goblet cell carcinoid (GCC) of the appendix is a rare tumor characterized by neuroendocrine and adenocarcinoma features. Accurate preoperative diagnosis is very difficult, with most patients complaining mainly of abdominal pain. Computed tomography shows swelling of the appendix, so diagnosis is usually made incidentally after appendectomy based on a preoperative diagnosis of appendicitis. Even if a patient undergoes preoperative colonoscopy, accurate endoscopic diagnosis is very difficult because GCC shows a submucosal growth pattern with invasion of the appendiceal wall.

Case Summary: Between 2017 and 2022, 6 patients with GCC were treated in our hospital. The presenting complaint for 5 of these 6 patients was abdominal pain. All 5 patients underwent appendectomy, including 4 for a preoperative diagnosis of appendicitis and the other for diagnosis and treatment of an appendiceal tumor. The sixth patient presented with vomiting and underwent ileocecal resection for GCC diagnosed from preoperative biopsy. Although 2 patients with GCC underwent colonoscopy, no neoplastic changes were identified. Two of the six patients showed lymph node metastasis on pathological examination. As of the last follow-up (median: 15 mo), all cases remained alive without recurrence.

Conclusion: As preoperative diagnosis of GCC is difficult, this possibility must be considered during surgical treatments for presumptive appendicitis.