[A case of coexisting malignant mesothelioma and squamous cell carcinoma of the lung].

We experienced a case of malignant mesothelioma with squamous cell carcinoma of the lung concurrently. A 40-year-old man presented with dyspnea. A massive pleural effusion was found by X-ray in the right side of his chest. Transcutaneous pleural biopsy yielded a diagnosis of malignant mesothelioma(IMIG cT4N0M0, Stage IV ). At the same time, his chest CT revealed tumor in the right hilar lesion. Transbronchial lung biopsy yielded a diagnosis of squamous cell carcinoma of the lung (cT3N0M0, Stage III B). Our diagnosis was double cancer, malignant mesothelioma and lung cancer. Chemotherapy with carboplatin, gemcitabine and radiation therapy was performed, but the patient died from deterioration of his systemic condition. We encountered a rare case of double cancer. More attention must be paid in making a diagnosis of malignant mesothelioma and lung cancer.