An Appendiceal Neoplasm that Presented as Mass-forming Acute Appendicitis Treated by Interval Appendectomy

Abstract

Mass-forming appendicitis is often treated via interval appendectomy (IA). However, some studies have suggested that occult appendiceal neoplasm can be masked by mass-forming appendicitis. We report a case of a low-grade appendiceal mucinous neoplasm manifesting as acute mass-forming appendicitis. Thus, the definitive diagnosis was made during IA. The patient was a 78-year-old man who underwent conservative treatment for his mass-forming appendicitis. Follow-up computed tomography imaging allowed us to diagnose appendiceal mucinous neoplasm. Laparoscopic ileocecal resection was done. Pathological examination revealed a low-grade appendiceal mucinous neoplasm. The patient has remained free of recurrence for four years. Thus, we suggest that IA may be a therapeutic technique for mass-forming appendicitis, especially in patients with possible occult appendiceal neoplasms.