High-grade and invasive neoplasms

High-grade and invasive neoplasms

Appendiceal mucinous tumours displaying high-grade dysplasia are classified as high-grade appendiceal mucinous neoplasm (HAMN). Mucinous tumours with infiltrative inva - sion are classified as mucinous adenocarcinoma and may be well, moderately or poorly di ff erentiated with or without the presence of signet ring cells. Non-mucinous adenocarcinoma is considered to be similar to typical colorectal cancer. Patients with high-grade tumour or invasive adenocarci noma are at risk of lymph node involvement. According to current paradigms, they should undergo right hemicolectomy . Because of the risk of peritoneal metastases, cytoreductive sur gery (CRS), to include right hemicolectomy with regional (right parietal) peritonectomy , omentectomy and HIPEC, may also be appropriate when the necessary expertise and experience are available. Considera tion may also be given to performing bilateral salpingo-oophorectomy because of the risk of tumour seeding to the ovaries, although in patients of childbearing age the decision making is complex.

L S TC C Figure 76.17 Pseudomyxoma peritonei with characteristic omental cake (C) encasing the transverse colon (TC) and extending to the greater curvature of the stomach (S). Tumour is seen to replace the lesser omentum (L).