Of the 2993 samples of appendectomies analyzed, 64 neoplasms of the appendix were found (35,9% benign, 18,8% premalignant, and 45,3% malignant as shown in Table 1), representing an incidence of 2,14%. The demographic characteristics of the subjects are summarized in Table 2. 67,2% were women, and the mean age for men was 46,4 years (± 19.5). In 89,1% of the cases, the diagnosis of acute appendicitis was determined through imaging, with a suspicion of an appendiceal tumor in 12,5% of them. In 78,1% of the cases, appendectomy was performed without requiring additional interventions. 98,4% of the procedures performed were through a laparoscopic approach and there was no need for conversion. The reintervention and complications rates were 0%. Of the cases that were diagnosed with appendiceal neoplasms, 14% were suspected intraoperatively.
The most frequent appendiceal neoplasm found was the neuroendocrine tumor (NET) reported in 27 patients (42,2%), of which 62,9% of the cases were women (Fig. 1), with an average age of presentation of 32.7 (± 12.3) years. In none of these patients, a tumor was suspected before the surgical procedure, and only in 2 cases (7,4%), there was an intraoperative suspicion of a tumor. According to the classification of the American Joint Committee of Cancer (AJCC) (26), well-differentiated tumors (G1) were found in 92,6% of the cases, while the remaining 7,4% were moderately differentiated (G2). 58.6% were tumors smaller than 1 cm, and only 2 specimens (6.9%) exceeded 2 cm in size (as shown in Table 3). In 89,7% of the cases, tumor-free resection margins were reported regarding malignant tumors.
The second most frequent tumor, corresponding to a benign pathology, was mucinous neoplasm of the appendix (AMN) reported in 23 samples (35,9%), of which 69,6% were women (Fig. 1). The average overall age of presentation was 62.1 (± 17) years. Suspicion of neoplasm in the computed abdominal tomography was made in 7 cases (30,4%), mucocele of the appendix was suspected in 6 patients, and the presence of a mass in the cecum was suspected in 1 case. An appendiceal tumor was suspected during the surgical procedure in 7 patients (30,4%). 86,9% were AMNs with a low degree of differentiation. In 7 of the samples, mucin content was found, and also 7 presented perforations (as shown in Table 4). In 82,6% of the cases, tumor-free resection margins were reported.
The sessile serrated adenoma (SSA), considered a pre-malignant lesion, was the third most frequent appendiceal tumor in this series, reported in 12 cases (18,8%). The mean age was 46 (± 15.6) years. Of the 12 SSAs, 9 cases (75%) were women (Fig. 1), and the average age of presentation was 44.8 years (± 15,8). In none of the patients, a tumor was suspected before or during the surgical procedure. 91,6% were SSAs without high-grade dysplasia. In 58,3% of the cases, tumor-free resection margins were reported.
The lowest frequency neoplasm found in the series was adenocarcinoma present in only 2 specimens (3,1%). The ratio of women to men was 1:1, with an average age of presentation of 54 years. One of the cases was reported as a well-differentiated neoplasm, and the other was poorly differentiated. Neither of the tumors was suspected before the surgical procedure. In one case, non-tumor-free resection margins were reported. Table 5 summarizes the surgical approach, according to the histopathological report of the appendectomy specimen.