Histopathologic Analysis in 46 Patients with Pseudomyxoma Peritonei Syndrome: Failure versus Success with a Second-Look Operation

Pseudomyxoma peritonei syndrome is a disease characterized by mucinous ascites and mucinous tumor disseminated on peritoneal surfaces; the disease almost always originates from a perforated

appendiceal epithelial tumor. Histopathologic assessment of aggressive versus noninvasive character of the mucinous tumor has been shown to have an impact on survival in patients treated

with cytoreductive surgery and intraperitoneal chemotherapy. Out of a database of 312 patients having a complete cytoreduction for pseudomyxoma peritonei syndrome, 46 patients (24 male and

22 female) had at least one second-look surgery. Before this review, all 46 of these patients were clinically uniformly categorized with a diagnosis of pseudomyxoma peritonei. Using the

criteria described by Ronnett and colleagues, all specimens from the multiple surgical procedures performed on these patients were reviewed and reclassified as disseminated peritoneal

adenomucinosis (adenomucinosis), adenomucinosis/mucinous adenocarcinoma (hybrid), or mucinous adenocarcinoma. The review was performed in a blinded fashion by a single pathologist (HY). To

facilitate a critical evaluation of these histopathologic assessments, the patients were separated into two groups: (1) 19 patients who had a second-look surgery that was unsuccessful in

that they went on to die of their disease or in that they currently have disease progression and a limited survival and (2) 27 patients who had a successful second look and currently

continue disease free with a minimum 3-year follow-up period. As a result of this review, 11 of 19 patients with an unsuccessful second look and originally designated pseudomyxoma peritonei

were reclassified as hybrid-type malignancy (four patients) or mucinous adenocarcinoma (seven patients). Only two patients were reclassified in the successful second-look group (P =.0005).

Transitions from a less aggressive to a more invasive histology from one cytoreduction to the next occurred on 13 occasions in patients whose second-look surgery failed and in one patient

with a successful second-look surgery (P