Optimizing the pathological diagnosis of diffuse malignant peritoneal mesothelioma

Area of Science:

• Oncology
• Surgical Pathology
• Diagnostic Accuracy

Background:

• Diffuse malignant peritoneal mesothelioma (DMPM) is the most common peritoneal mesothelioma (PM).
• Accurate histology and Ki67 assessment are critical for DMPM treatment and prognosis.
• Intra-tumoral heterogeneity complicates preoperative diagnostics, and a standardized pathway is lacking.

Purpose of the Study:

• To evaluate factors influencing diagnostic accuracy of Ki67 and sarcomatoid component in DMPM.
• To compare the diagnostic performance of core-needle biopsy versus surgical biopsy for DMPM.
• To assess the impact of biopsy type, number, and specimen volume on diagnostic concordance.

Main Methods:

• Retrospective analysis of 98 DMPM patients (2008-2022).
• Estimation of concordance between preoperative and post-CRS-HIPEC histology and Ki67-class using the k-index.
• Fisher's exact test to assess the impact of biopsy type, number, and specimen quantity on diagnostic accuracy.

Main Results:

• Optimal concordance for histotype (k=0.8) and moderate for Ki67 (k=0.4).
• Biopsy type, number, and volume did not significantly impact histotype or Ki67 concordance.
• Surgical biopsy demonstrated high sensitivity and specificity for sarcomatoid component and Ki67 assessment; core-needle biopsy showed high specificity but lower sensitivity for Ki67.

Conclusions:

• Surgical biopsy remains the gold standard for DMPM diagnosis.
• Core-needle biopsy is a viable alternative for lesions accessible via interventional radiology.
• Further standardization of diagnostic pathways for DMPM is needed.