[Management of carcinomatous metastatic pleurisy with unknown primary neoplasm]

The primary cancer remains unknown in about 7% of all cases of metastatic carcinomatous pleurisy. Thoracoscopic pleural biopsy provide good quality histology material. The pathology examination, including immunohistochemistry using a panel of well-defined antibodies can provide the diagnosis of neoplastic pleurisy of malignant carcinomatous proliferation, and help search for differentiation and rule out an identifiable primary carcinoma. When histology does not provide a satisfactory clue to the primary cancer, frequent origins include lung cancer, breast or ovary cancer in women, prostate cancer in men, and digestive tract cancer. The possible contribution of positron emission tomography remains to be evaluated. Several chemotherapy protocols can be proposed but the beneficial effect has been difficult to assess due to the heterogeneous nature of the histological forms treated. The carboplatin-paclitaxel-etoposide protocol appears to be promising in cases with an unknown primary cancer but there has been no specific assessment of this chemotherapy schedule in a subgroups of patients with carcinomatous pleurisy with an unknown primary cancer. Better understanding of the biological profile of highly metastatic cancers should be helpful in determining more targeted therapeutic schemes.