Chong Wang

Purpose To compare noncontrast multiparametric MRI (mpMRI) and contrast-enhanced CT (CECT) for agreement with intraoperative peritoneal cancer index (PCI) and detection of key imaging features in pseudomyxoma peritonei (PMP). Materials and Methods This retrospective study included 40 patients with pathologically confirmed PMP who underwent cytoreductive surgery and preoperative mpMRI and CECT in 2024. Intraoperative PCI across 13 abdominopelvic regions served as the reference standard. Total PCI agreement was assessed using intraclass correlation coefficients (ICCs) and Bland–Altman 95% limits of agreement (LoA), with analyses stratified by PCI (≤ 20 vs > 20). Regional agreement and sensitivities for key imaging features were also compared. Results Forty patients (median age, 60 years; 25 women) were included. mpMRI showed greater agreement with intraoperative total PCI than CECT (ICC, 0.98 vs 0.90; difference, 0.08 [95% CI: 0.05, 0.15]), with narrower LoA (7.1 vs 19.1 points). Agreement remained greater with mpMRI for PCI ≤ 20 (ICC, 0.91 vs 0.58) and PCI > 20 (ICC, 0.95 vs 0.74). mpMRI showed higher regional agreement in 11 of 13 regions after multiple-comparison correction. mpMRI had higher sensitivity for mucinous ascites (100% vs 61%; P = 0.002) and intralesional septation (95% vs 37%; P = 0.002), whereas CECT had higher sensitivity for intralesional calcification (100% vs 0%; P = 0.021). Conclusion Noncontrast mpMRI showed greater agreement with intraoperative PCI than CECT and higher sensitivity for mucinous ascites and intralesional septation, whereas CECT better detected intralesional calcification.

The management of incidental appendiceal mucinous neoplasm (IAMN) was confusing with difficult decision-making. This study was to investigate the association of variables from the initial operation to cytoreductive surgery with overall survival (OS). One hundred thirty patients of IAMN treated at Aerospace Center Hospital were retrospectively analyzed from January 2014 to December 2020. A total of 82 IAMN patients who underwent reoperation with cytoreductive surgery (CRS) and had available data on the date of their initial operation was included. Of these 82 IAMN patients, the mean time from the initial operation to CRS was 19 months (1–146 months). The 5-year OS rate was 69.8%, and the median OS was 39 months (1–73 months). The patients who underwent CRS within 6 months had a higher radical rate (63.3% vs 36.7%) with lower tumor burden and better survival. No significant difference was found in patients with right hemicolectomy or prior systemic chemotherapy. Multivariate analysis identified the completeness of cytoreduction score and the pathologic subtype of peritoneal pseudomyxoma (PMP) as independent prognostic factors. Extended surgery and systematic chemotherapy are not suitable for IAMN patients. It is more important to identify the pathology and accept standard therapy in academic medical centers within 6 months.

Background: Pseudomyxoma peritonei (PMP) is a rare peritoneal malignancy with limited genomic data across different biospecimen types. The extent to which ascites and plasma reflect tissue-detected genomic alterations remains incompletely characterized. This study compared genomic profiles across tumor tissue, ascites, and plasma and explored KRAS-defined molecular features in PMP. Methods: Sixty patients with pathologically confirmed PMP were retrospectively included. Next-generation sequencing (NGS) data were available from tumor tissue in 57 patients, ascites in 40, and plasma in 28, with overlapping specimen availability. Cross-specimen genomic concordance was evaluated in 37 patients with matched tissue–ascites samples, including 28 patients with matched tissue, ascites, and plasma. Exploratory analyses were performed to characterize genomic and pathway-level features across KRAS-defined subgroups. Results: In tumor tissue, KRAS (66.7%), GNAS (31.6%), and TP53 (21.1%) were the most frequently altered genes. Among 28 patients with matched tissue, ascites, and plasma, patient-level concordance was 35.7%. At the mutation level, ascites showed higher tissue-referenced positive percentage agreement (PPA) than plasma (93.1% vs. 36.2%). In the expanded cohort of 37 matched tissue–ascites pairs, ascites achieved a tissue-referenced PPA of 94.2% and revealed additional alterations not detected in the corresponding tissue samples. Exploratory KRAS mutation stratification identified G12D (35.0%), G12X (32.5%), and KRAS-wild-type (wt) (17.5%) tumors as the predominant subgroups. KRAS-mutant tumors harbored more detected genomic alterations and potentially clinically actionable alterations than KRAS-wt tumors. Wnt and PI3K pathway alterations were more commonly observed in the G12D and G12X subgroups, respectively, whereas canonical oncogenic pathway alterations were less frequent in KRAS-wt tumors. Conclusions: PMP exhibits substantial genomic heterogeneity across patients and biospecimen types. Ascites cfDNA showed high concordance with tissue and captured additional genomic alterations, suggesting that ascitic fluid may serve as a complementary source for molecular profiling in PMP. KRAS-defined subgroups exhibited distinct genomic characteristics, although their clinical relevance requires further validation in larger, well-characterized cohorts.

Pseudomyxoma peritonei (PMP) is a rare peritoneal malignancy. Its typical clinical manifestations include abdominal distension, increased abdominal girth, or abdominopelvic masses. It is extremely rare for an umbilical hernia to be the initial manifestation, so this can easily lead to clinical misdiagnosis. A 60-year-old woman presented with a reducible umbilical mass for 10 months. Physical examination revealed marked abdominal distension and a 6-cm firm, irreducible umbilical mass. Serum tumor markers were normal. Computed tomography (CT) showed diffuse low-density abdominopelvic masses consistent with PMP, an appendiceal cystic lesion suggestive of mucinous neoplasm, omental thickening, and periumbilical tumor extension. Ultrasound revealed 9.4-cm ascites with mucin particles and septations. She underwent cytoreductive surgery with hyperthermic intraperitoneal chemotherapy. Intraoperatively, extensive gelatinous mucin, a ruptured cystic appendix, and periumbilical tumor involvement were noted. Postoperative pathology confirmed a high-grade appendiceal mucinous tumor with PMP. The immunohistochemistry results were as follows: cytokeratin 20 positive, caudal type homeobox 2 positive, and Ki-67 labeling index of 30%. Telephone follow-up 3 months after surgery indicated that the patient was doing well. PMP presenting with umbilical hernia as the initial symptom is relatively rare and is often misdiagnosed as a simple umbilical hernia. For middle-aged and elderly female patients with umbilical hernia who have concurrent ascites, thickened peritoneum, or a hard and fixed hernia mass, abdominopelvic CT and ultrasound should be performed to rule out PMP to avoid blindly performing hernia repair and delaying diagnosis and treatment.

The necessity of prophylactic cytoreductive surgery (PCRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for low-grade appendiceal mucinous neoplasms (LAMN) after complete removal is still controversial. This study aims to determine the role of PCRS + HIPEC and identify optimal strategies for managing these patients. One hundred fifty-nine patients who sought medical advice at Aerospace Center Hospital were retrospectively analyzed from January 2011 to December 2021. All the patients were divided into the PCRS group and the observation group. The data of surgical specimens and pathology was collected, and the effect on recurrence-free survival (RFS) was analyzed. Of these 159 patients, 88 were in the PCRS group, and 71 were in the observation group. The median follow-up time was 38 months. Seven patients recurred and developed into pseudomyxoma peritonei, 1 in the PCRS group and 6 in the observation group. The analysis of RFS showed that patients who underwent PCRS (P = .01) and HIPEC (P = .01) had better survival. After multivariate analysis, the surgical specimen accompanied by disseminated peritoneal adenocarcinoma was identified as an independent prognostic factor for RFS. In the study of surgical resection content, patients with greater omentum (P = .01) and bilateral fallopian tubes and ovaries of women (P = .002) resection had a more prolonged RFS with statistical significance. The research indicated that PCRS + HIPEC could prevent recurrence. Therefore this treatment were necessary for LAMN after complete removal in patients with a high risk of recurrence. However, it was not proven to be an independent factor for RFS, and a multicenter, prospective, randomized trial was need to definitively address the role of PCRS + HIPEC for LAMN after complete resection.