[Appendiceal goblet cell adenocarcinoma: Has the controversy come to an end?]

Abstract

In 2019, the 5th edition of the WHO classification of digestive tumours has retained the terminology "goblet cell adenocarcinoma" (GCA) to designate a tumour whose amphicrine nature owed it more than ten denominations since its initial description among which the most tenacious "goblet cell carcinoid" is no longer recommended today. This rare tumour represents 15-19% of appendicular tumours. Its incidence is rising. The positive diagnosis is based on morphological examination and mandatory identification of a low-grade component of glands comprising goblet cells stained by PAS and Alcian blue. The appendix must be entirely examined. Global tumour grade (low, intermediate, high) is based on the proportions of low-grade and high-grade components. This tumour's immunohistochemical profile is particular because of expression of CK20 and often CK7 as well as neuroendocrine markers. It is often an incidental finding on a surgical specimen, among individuals aged 50 or more years, presenting with a locally advanced stage with vascular and perineural invasion. Lymph node metastases are present in a third of cases. Non-specific mutations of ARID1A and genes of the Wnt pathway may be identified. GCA is not associated with microsatellite instability or Lynch syndrome. Its prognosis is intermediate. Surgery is the reference therapy based on the stage. The main differential diagnoses are colorectal adenocarcinoma NOS, mucinous adenocarcinoma and signet ring cell adenocarcinoma. Patients are referred to the RENAPE expert network.