MKI67 and atypical carcinoid tumor: The indications for a complementary surgery include histological evidence of mesoappendiceal extension [12], tumor at the base of the appendix with positive margins or involvement of the caecum [13], high-grade malignant carcinoid tumor with a raised tumor prognostic index as measured by mitotic index and Ki-67 levels [12], lymph node involvement, and cellular pleomorphism with a high mitotic index [14].