Appendiceal Neoplasms

Abstract

Primary appendiceal neoplasms are rare and most commonly diagnosed incidentally, upon histological analysis of the appendectomy specimen. The timing and circumstances of the diagnosis, tumor histology, staging, required resection margin, and the probability of nodal disease are factors of consideration to determine the further management of such patients. In many instances further surgery is indicated. The tumors are classified as epithelial (mucinous and non-mucinous), non-epithelial (carcinoids, and others), or mixed tumors (goblet cell carcinoid). Epithelial tumors represent the most common appendiceal tumors. Apart from direct invasive growth, lymphogenous and hematogenous spread, particularly mucin-producing lesions can result in a mucocele, perforate, and thus lead to dissemination of tumor cells and mucin into the peritoneal cavity to form pseudomyxoma peritonei. For localized disease, the goal is to achieve a curative R0 resection either by appendectomy alone or by a formal right hemicolectomy. Metastatic disease requires an individualized approach weighing systemic chemotherapy against cytoreductive surgery with HIPEC in select cases. Neuroendocrine tumors (carcinoids) are non-epithelial and often hormone-active argentaffin/argyrophilic tumors that derive from the dispersed enterochromaffin cells of the gastrointestinal tract and can metastasize to regional lymph nodes and distant organs. The aggressiveness of the surgical approach depends on tumor size as the most important parameter of the primary tumor staging, the location of the tumor, and presence or absence of regional or distant metastases.