Primary cancers of the appendix are rare and are frequently diagnosed after surgery for appendicitis, presumed ovarian primary malignancy, or other indications. Primary appendix cancers are histologically diverse, and classification of these tumors has historically been confusing because of the nonstandardized nomenclature that is used. This review aimed to describe the epidemiology, presentation, workup, staging, and management of primary appendix cancers using current, recommended nomenclature. For this purpose, tumors were broadly classified as colonic-type or mucinous adenocarcinoma, goblet cell adenocarcinoma, or neuroendocrine carcinoma. Signet ring cell carcinoma was not regarded as an individual entity. The presence of signet ring cells is a histologic feature that may or may not be present in colonic-type or mucinous adenocarcinoma. The management of primary appendix cancer is complex and is dependent on the histologic subtype and extent of disease. Randomized, prospective trials do not exist for these rare tumors and management is largely guided by retrospective data expert consensus guidelines, which are summarized here.
Keywords: colonic-type adenocarcinoma; goblet cell adenocarcinoma; mucinous adenocarcinoma; neuroendocrine carcinoma.