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Updated: Dec 25, 2025
Culture and Imaging of Ex Vivo Organotypic Pseudomyxoma Peritonei Tumor Slices from Resected Human Tumor Specimens
Published on: December 9, 2022
Pseudomyxoma peritonei: visceral scalloping on CT is a predictor of recurrence after complete cytoreductive surgery
Masatoshi Hotta1, Ryogo Minamimoto2, Yoshimasa Gohda3
1Department of Radiology, National Center for Global Health and Medicine, 1-21-1, Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan. masatoshihotta@yahoo.co.jp.
Objectives:
Pseudomyxoma peritonei (PMP) is characterized by peritoneal dissemination of gelatinous ascites following rupture of a mucinous tumor. Treatment by cytoreductive surgery (CRS) has improved its prognosis. Although visceral scalloping, notably liver scalloping, on computed tomography (CT) is a typical feature of PMP, its prognostic value remains unknown. We aimed to investigate the efficacy of liver scalloping in predicting recurrence in PMP patients.
Methods:
Among 159 consecutive patients with PMP who had contrast-enhanced CT between September 2012 and December 2018, 64 treatment-naïve patients who subsequently underwent CRS with complete resection (i.e., completeness of cytoreduction score (CC)-0 or CC-1), were included in analysis. Presence of liver scalloping and maximum thickness of mucin deposition at the liver surface were evaluated on CT. Disease-free survival (DFS) was determined based on the combination of postoperative CT features and tumor marker values.
Results:
Median follow-up was 24.3 months. CT revealed liver scalloping in 40/64 (63.4%) patients. Kaplan-Meier analysis showed significantly shorter DFS in patients with scalloping than in those without (p = 0.001; hazard ratio, 4.3). In patients with scalloping, greater mucin deposition (thickness ≥ 20 mm) significantly correlated with poorer DFS (p = 0.042). In multivariate Cox proportional hazards regression including CC status, pathologic type, and tumor markers, the presence of scalloping independently and significantly correlated with DFS (p = 0.031).
Conclusions:
Liver scalloping was an independent predictor even after adjusting for clinical covariates. The presence of liver scalloping can lead to a high recurrence rate after CRS.
Key Points:
• The presence of liver scalloping is a prognostic factor independent of histological grade and tumor markers. • Greater mucin deposition (thickness ≥ 20 mm at the liver surface) is associated with higher recurrence rates in patients with liver scalloping.
Insights
Liver scalloping on CT scans predicts higher recurrence rates in pseudomyxoma peritonei (PMP) patients after cytoreductive surgery (CRS). Greater mucin deposition indicates a poorer prognosis, highlighting scalloping as an independent prognostic factor.
Area of Science:
- Oncology
- Radiology
- Surgical Pathology
Background:
- Pseudomyxoma peritonei (PMP) involves peritoneal spread of mucinous tumor contents.
- Cytoreductive surgery (CRS) has improved PMP prognosis.
- Liver scalloping on CT is a typical PMP feature, but its prognostic significance is unclear.
Purpose of the Study:
- To evaluate the prognostic value of liver scalloping in predicting recurrence in PMP patients.
- To determine if liver scalloping is an independent predictor of disease-free survival (DFS) after CRS.
Main Methods:
- Retrospective analysis of 64 treatment-naïve PMP patients who underwent complete CRS.
- Contrast-enhanced CT scans were used to assess liver scalloping and mucin deposition thickness.
- Disease-free survival (DFS) was analyzed using Kaplan-Meier and Cox regression models.
Main Results:
- Liver scalloping was present in 63.4% of patients.
- Patients with liver scalloping had significantly shorter DFS (p=0.001).
- Greater mucin deposition (≥20 mm) in scalloped areas correlated with poorer DFS (p=0.042).
- Liver scalloping was an independent predictor of DFS in multivariate analysis (p=0.031).
Conclusions:
- Liver scalloping is an independent prognostic factor for PMP recurrence after CRS.
- The presence and extent of liver scalloping, particularly mucin deposition thickness, can guide risk stratification and patient management.
