[Incidental Finding of Appendiceal Neuroendocrine Tumour]. / Zufallsbefund NEN Appendix.

With an incidence of 80%, neuroendocrine neoplasia (NEN) is the most common neoplasia of the appendix. In most cases, these tumours are diagnosed as an incidental finding after appendectomy with suspected appendicitis. They are usually highly differentiated neuroendocrine tumours. Due to their frequent location on the apex of the appendix, the NENs of the appendix are usually not the cause of the symptoms typical for appendicitis.Most patients (80-90%) receive adequate oncological treatment by laparoscopic or open appendectomy that has already been performed. However, if there are risk factors such as tumour size > 2 cm, location close to the base, angioinvasion, perforation or infiltration of neighbouring organs, proliferation index of > 2% or infiltration of the mesoappendix by more than 3 mm in the final histopathological finding, subsequent resection as an oncological right sided hemicolectomy is recommended .Due to their mostly early tumour stage at diagnosis without proven lymph node metastasis, patients with NEN of the appendix have an excellent 5-year survival rate of 70-85% across all tumour stages.