Objective: To investigate clinicopathological features and prognostic factors of appendiceal neuroendocrine neoplasms(a-NEN).
Methods: Clinical data of 20 patients diagnosed with a-NEN at Zhongshan Hospital of Fudan University between January 2000 and December 2016 were retrospectively analyzed. Pathological diagnosis was based on the WHO classification criteria of digestive system tumors (2010 edition). Based on the mitotic count and Ki-67 index, a-NENs were divided into grade 1 neuroendocrine tumor (NET G1), grade 2(G2) NET G2) and grade 3 (neuroendocrine carcinoma, NEC). Some special types of a-NEN (e.g. goblet cell carcinoid) and mixed adenoneuroendocrine neoplasms were classified as mixed adenoneuroendocrine carcinoma (MANEC). Follow-up was conducted by telephone or return visits. Univariate analysis was carried out using the Kaplan-Meier method, and the log-rank test was used to draw survival curves.
Results: Of 20 patients, 14 were male and 6 were female with median age of 54 years. Seventeen cases presented acute right lower quadrant abdominal pain, 1 chronic right lower quadrant abdominal pain, 1 persistent abdominal discomfort with outburst whole abdominal pain and 1 was found during body check without symptoms. Twenty cases comprised 8 G1 patients, 4 G2 patients, 3 G3 patients, and 5 MANEC patients. When diagnosed, there was 1 patient with liver metastasis, 1 patient with abdominal and pelvic metastases, and 2 patients with postoperative pathological findings of lymph node metastasis. Six patients underwent appendectomy, 12 underwent right hemicolectomy, 1 underwent right hemicolectomy plus small intestine resection, and 1 underwent partial hepatectomy plus right hemicolectomy. The follow-up time was 7-187 months(average, 36 months). The total 1- and 3-year survival rates were 94.7% and 60.2%, respectively. Univariate analysis showed that age >50 years (χ2=7.036, P=0.008), pathology grade as MANEC (χ2=5.297, P=0.021), and metastasis (χ2=6.558, P=0.010) indicated lower 5-year survival rate.
Conclusions: Most a-NEN patients have no typical symptoms, and the main complaint at consultation is acute right lower quadrant abdominal pain. Prognosis is poor for patients with age >50 years, MANEC pathology grade and metastasis.