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Optimizing the pathological diagnosis of diffuse malignant peritoneal mesothelioma
F L Nava1, S Kusamura2, M Shimonovitz-Moore3
1Peritoneal Surface Malignancy Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy; General Surgery Residency Program, Università degli Studi di Milano, Italy.
Background:
Diffuse malignant peritoneal mesothelioma (DMPM) is the most common histological type of peritoneal mesothelioma (PM). Accurate histology and Ki67 assessment are crucial for treatment and prognosis, yet intra-tumoral heterogeneity may hinder preoperative diagnostics. A standardized diagnostic pathway is lacking. This study evaluates factors influencing the diagnostic accuracy on Ki67 and sarcomatoid component.
Materials And Methods:
This retrospective study analysed 98 patients (2008-2022). Concordance between preoperative and post-CRS-HIPEC histological subtype and Ki67-class (≤9 % vs. >9 %) was estimated using the k-index. Fisher's exact test assessed the impact of biopsy type (core-needle vs. surgical), biopsy number (single vs. multiple), and specimen quantity (slides and blocks) on histotype and Ki67 concordance. Diagnostic performance was evaluated for both core-needle and surgical biopsy.
Results:
Concordance was moderate for Ki67 (k-index = 0.4) and optimal for histotype (k-index = 0.8). No significant differences were found between biopsy types for histotype (p = 0.60) or Ki67 (p = 1.00). Diagnostic accuracy was unaffected by biopsy number (p = 0.16 histotype, p = 0.50 Ki67) or volume (p = 0.30 histotype, p = 0.60 Ki67). Surgical biopsy had Sensibility (Se) = 80 %, Specificity (Sp) = 98 %, Positive Predictive Value (PPV) = 80 %, Negative Predictive Value (NPV) = 98 % for sarcomatoid identification, and Se = 86 %, Sp = 82 %, PPV = 79 %, NPV = 88 % for Ki67. Core-needle biopsy showed Se = 60 %, Sp = 100 %, PPV = 100 %, NPV = 50 % for Ki67.
Conclusions:
Surgical biopsy remains the current gold standard for PM diagnosis, but core-needle biopsy could be considered for lesions accessible via interventional radiology.
Insights
Accurate diagnosis of diffuse malignant peritoneal mesothelioma (DMPM) is vital. Surgical biopsy is the gold standard, but core-needle biopsy shows promise for specific cases, improving diagnostic accuracy for peritoneal mesothelioma (PM).
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.
