[Malignant mesothelioma. Retrospective study of 16 cases]

Sixteen cases of malignant mesothelioma (13 pleural and 3 peritoneal) are reported. Fifteen cases were autopsied; in one case only biopsy material was available which are studied by electron microscopy. Among the autopsy cases, 12 had had previous biopsies, one had undergone multiple cytological examinations and 2 cases only one cytological examination. It was concluded that clinical signs and symptoms of mesothelioma were not specific and did not allow the diagnosis. For differential diagnosis as between mesothelioma and metastatic carcinoma, biopsy seemed to be more reliable that exfoliative cytology. Alcian blue stain after hyaluronidase digestion is a reliable test in the diagnosis of mesothelioma only when alcian blue is positive initially. However, in half of our mesothelioma cases this stain remained negative. Electron microscopic study appeared to be a satisfactory method of differentiating between malignant mesothelioma and metastatic carcinoma.