Lymph node positive pseudomyxoma peritonei

Abstract

Background: Appendiceal mucinous neoplasms are routinely accompanied by peritoneal metastases at the time of diagnosis of the primary appendiceal tumor. In contrast, liver metastases and lymph node metastases are unusual.

Methods: From an extensive database, patients with lymph node metastases identified at the time of primary appendiceal cancer resection were selected for special study. The clinical, treatment-related and histologic variables of this group of patients were statistically analyzed for their impact on overall survival.

Results: From a prospectively maintained database of 685 patients with a complete cytoreduction of a mucinous appendiceal neoplasm with peritoneal dissemination, 39 patients (5.6%) had lymph node metastases at the time of primary diagnosis. The median follow-up was 5.0 years and overall median survival was 6.0 years. Histologically, 6 of these patients (15.4%) had an appendiceal mucinous neoplasm - Intermediate type (MACA-Int). In 5 patients, the involved lymph nodes were not within the ileocolic lymph node group. The 7 patients (17.9%) who had a complete or near complete response to neoadjuvant chemotherapy prior to definite cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) showed prolonged survival (HR 4.8 (1.1, 20.5) p = 0.0323). A prior right colon resection required repeat resection in 87% of patients.

Conclusion: Long-term survival is unusual but occasionally seen in this group of patients. Response to neoadjuvant chemotherapy is an important determinant of a favorable outcome.

Keywords: Appendiceal mucinous neoplasm; Cytoreductive surgery; EPIC; HIPEC; Mucocele; Mutations; Neoadjuvant chemotherapy; Peritonectomy; Tumorigenesis.