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Updated: Dec 31, 2025
Culture and Imaging of Ex Vivo Organotypic Pseudomyxoma Peritonei Tumor Slices from Resected Human Tumor Specimens
Published on: December 9, 2022
Pathological prognostic factors of pseudomyxoma peritonei: comprehensive clinicopathological analysis of 155 cases
Fengcai Yan1, Yulin Lin2, Quan Zhou1
1Department of Pathology, Beijing Shijitan Hospital, Capital Medical University, Beijing 100038, China.
Background:
Pseudomyxoma peritonei (PMP) is an extremely rare malignancy, characterized by extensive peritoneal implantation and colloidal ascites. This study was to explore the pathological prognostic factors of PMP.
Methods:
Specimens from 155 PMP patients were analyzed by H&E and immunohistochemistry. Parameters included primary tumor location, histological grade, lymph node metastasis, tumor emboli in the blood and lymph vessels, perineural invasion, Ki67 labeling index, p53, mismatch repair (MMR) gene mutations, MUC1, MUC2, MUC5AC, and MUC6. Clinicopathological and follow-up data were subjected to univariate and multivariate analyses.
Results:
The patients included 63.2% (n = 98) low-grade mucinous carcinoma peritonei, 31.6% (n = 49) high-grade mucinous carcinoma peritonei and 5.2% (n = 8) high-grade mucinous carcinoma peritonei with signet ring cells. There were 9.7% (n = 15) with lymph node metastasis; 11.6% (n = 18) with angiolymphatic invasion; 6.3% (n = 8) with defective MMR (dMMR); 35.5% (n = 55) with Ki67 labeling index ≥ 50%; 36.1% (n = 56) with p53 mutation. For PMP from appendiceal origin (n = 140), univariate analysis identified 10 potential prognostic factors. But Multivariate analysis identified only histologic grade was the independent prognostic factor for OS. Mortality risk of high-grade peritoneal mucinous carcinoma or high-grade peritoneal mucinous carcinoma with signet ring cells was 7.056 times (P < .0001, 95% CI: 2.701-18.435) or 27.224 times (P < .0001, 95% CI: 6.207-119.408), respectively, higher than low-grade.
Conclusions:
For PMP from the appendiceal origin, histological grade could be the only independent prognostic factor.
Insights
Histological grade is the sole independent prognostic factor for overall survival in pseudomyxoma peritonei (PMP) originating from the appendix. High-grade PMP significantly increases mortality risk compared to low-grade tumors.
Area of Science:
- Oncology
- Pathology
Background:
- Pseudomyxoma peritonei (PMP) is an exceptionally rare malignancy characterized by extensive peritoneal spread and mucinous ascites.
- Identifying pathological prognostic factors is crucial for understanding PMP progression and patient outcomes.
Purpose of the Study:
- To investigate the pathological prognostic factors influencing overall survival in patients with pseudomyxoma peritonei.
- To determine the independent prognostic significance of various clinicopathological parameters in PMP.
Main Methods:
- Analysis of 155 PMP patient specimens using Hematoxylin and Eosin (H&E) staining and immunohistochemistry.
- Evaluation of parameters including primary tumor location, histological grade, lymph node metastasis, angiolymphatic invasion, Ki67 index, p53, and mismatch repair (MMR) gene status.
- Univariate and multivariate analyses were performed on clinicopathological and follow-up data.
Main Results:
- Histological grade was identified as the only independent prognostic factor for overall survival in PMP of appendiceal origin (n=140).
- High-grade mucinous carcinoma peritonei and high-grade mucinous carcinoma peritonei with signet ring cells showed significantly increased mortality risks (7.056-fold and 27.224-fold, respectively) compared to low-grade PMP.
- Other factors like lymph node metastasis and angiolymphatic invasion were not independent predictors in multivariate analysis.
Conclusions:
- For PMP originating from the appendix, histological grade is the sole independent prognostic factor for overall survival.
- This finding underscores the critical importance of accurate histological grading in PMP patient management and prognosis.
