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Updated: Oct 10, 2025
Culture and Imaging of Ex Vivo Organotypic Pseudomyxoma Peritonei Tumor Slices from Resected Human Tumor Specimens
Published on: December 9, 2022
Progression to pseudomyxoma peritonei in patients with low grade appendiceal mucinous neoplasms discovered at time of
Shelby Reiter1, Colin J Rog1, Mohamed Alassas1
1Department of Surgery, Division of Surgical Oncology, Swedish Medical Center, 747 Broadway, Heath 10, Suite 1003, Seattle, WA, 98122, USA.
Background:
The discovery of a low grade appendiceal mucinous neoplasm (LAMN) during appendectomy is a rare scenario. These neoplasms can progress to pseudomyxoma peritonei (PMP), however the incidence of progression is not well known.
Methods:
The records of all patients with a diagnosis of localized LAMN found during appendectomy were identified, and demographic, tumor, surveillance, and outcome variables were analyzed.
Results:
Progression to PMP occurred in 20% of patients in an average of 12.4 months after appendectomy with median follow-up of 18 months. Tumor variables such as margin positivity, appendiceal perforation, and presence of extra-appendiceal acellular mucin or mucinous epithelium on the serosal were not significantly associated with progression.
Conclusions:
During an average follow-up period of 18 months after surgery, progression to PMP occurred in a fifth of patients. It is difficult to predict which patients will progress, therefore cross-sectional imaging surveillance is recommended for all patients.
Insights
A low-grade appendiceal mucinous neoplasm (LAMN) discovered during appendectomy can progress to pseudomyxoma peritonei (PMP) in 20% of cases. Due to unpredictable progression, regular imaging surveillance is recommended for all patients.
Area of Science:
- Gastroenterology
- Oncology
- Surgical Pathology
Background:
- Low-grade appendiceal mucinous neoplasm (LAMN) is rarely found during appendectomy.
- LAMN can potentially progress to pseudomyxoma peritonei (PMP).
- The incidence and predictors of LAMN progression are not well-established.
Purpose of the Study:
- To analyze the progression rate of localized LAMN to PMP after appendectomy.
- To identify potential risk factors for LAMN progression.
- To establish surveillance recommendations for patients with LAMN.
Main Methods:
- Retrospective analysis of patient records with localized LAMN diagnosed during appendectomy.
- Evaluation of demographic, tumor, surveillance, and outcome variables.
- Statistical analysis to determine progression to PMP and associated factors.
Main Results:
- Progression to PMP occurred in 20% of patients within an average of 12.4 months post-appendectomy.
- Median follow-up was 18 months.
- Tumor characteristics like margin status, perforation, or mucin presence did not significantly predict progression.
Conclusions:
- Approximately one-fifth of patients with LAMN progress to PMP within 18 months.
- Predicting progression is challenging based on initial tumor variables.
- Cross-sectional imaging surveillance is advised for all patients diagnosed with LAMN.
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