Rare Appendicular Pathologies: Diagnostic Challenges, Surgical Management, and Outcomes in a Retrospective Tertiary-Center Cohort with Literature Review.

Background: Rare appendicular pathologies (RAP) are uncommon clinical entities with important diagnostic and therapeutic implications. These conditions frequently mimic acute appendicitis, yet they may require different operative strategies and, in selected cases, oncological management. Methods: We performed a retrospective cohort study including all patients who underwent surgery with the intention of performing an appendectomy at the First Surgical Clinic, Emergency County University Hospital of Cluj-Napoca, between 2018 and 2021. During this interval, 330 appendectomies were performed. Patients with a histopathological diagnosis of RAP were included. Clinical, imaging, surgical, histopathological, postoperative, and follow-up data were analyzed, with particular attention to the preoperative diagnostic work-up and imaging-based suspicion of rare appendicular pathology. Results: Ten patients (3.03%) were diagnosed with RAP, including low-grade appendiceal mucinous neoplasm (LAMN; n = 5), mucinous cystadenoma (n = 2), appendiceal adenocarcinoma (n = 1), appendicular diverticulum (n = 1), and stump appendicitis (n = 1). Computed tomography was the main diagnostic modality, particularly in patients with atypical presentation or suspicion of complicated or neoplastic appendiceal disease, while magnetic resonance imaging and colonoscopy provided additional information in selected cases. Preoperative suspicion of a rare or neoplastic appendiceal pathology was achieved in 70% of patients. Laparoscopic appendectomy was performed in 6 patients, open appendectomy in 1 patient, open ileocecal resection in 1 patient, open right hemicolectomy in 1 patient, and laparoscopic right hemicolectomy in 1 patient. Histopathological examination confirmed the diagnosis in all cases. Immediate postoperative outcomes were favorable, without perioperative mortality or major complications; during follow-up, the patient with adenocarcinoma required oncological treatment and resection of a local recurrence 1 year after surgery. Conclusions: RAP represent a small but clinically significant subset of appendiceal disease. Structured preoperative imaging, intraoperative recognition of atypical findings, and an individualized surgical strategy are essential for optimal outcomes and appropriate oncological management.