Malignant pleural effusion is a common evolution of various cancers and is associated with poor prognosis and quality of life. About 28% of patients with primary malignancy will develop pleural metastasis. Malignant pleural effusion mostly occurs in lung, breast, ovarian and gastric cancers. Median survival ranges from 3 to 13 months according to primary malignancy. Currently, the therapeutic approach is mainly palliative with videothoracoscopic talc pleurodesis or indwelling pleural catheters insertion eventually associated with systemic chemotherapy if patient's general condition allows.

In a early-disseminated tumor cells profile, metastatic cells can accumulate alterations at a distant site and have a different profil from the original tumor cells. Metastatic cells can also accumulate alterations in the course if systemic treatments. Consequently, they may respond differently to drugs.

Recently, EGFR mutations and ALK status discordance between primary tumors and pleural metastases have been demonstrated in a significant portion of lung adenocarcinomas. These studies, realized on malignant pleural effusion isolated cells, enabled us to hypothesize a possible intratumoral heterogeneity within pleural metastases, but no study has been carried out on pleural tissue.

Our aim is to create a biocollection with tissues from pleural carcinomatosis in order to subsequently allow multiomics and bioinformatics analyzes and to characterize a possible intratumoral heterogeneity in pleural metastasis.

Inclusion Criteria:

• Male or female over 18 years old
• Malignant pleural effusion with or without prior histological or cytological diagnosis
• Patient eligible for a pleural biopsy for diagnostic purposes and validated in a multidisciplinary consultation meeting
• Having given their free and informed writing consent
• Affiliated to a social security system or assimilated

Exclusion Criteria:

• Malignant pleural mesothelioma
• Contraindication to general anesthesia
• Pregnant or breastfeeding woman, or is of child bearing potential and who did not agree to use highly effective methods of birth control throughout the study.
• Patient participating in a interventional study likely to interfere with this study
• Patient benefiting from a legal protection measure (guardianship or curatorship)

This study concerns adult patients with pleural metastasis eligible for a surgical exploration of the pleura