Localized malignant mesothelioma of the pleura.

Because malignant mesothelioma is commonly seen as a diffuse neoplasm, a localized tumor is an extremely rare form of presentation. Only 45 cases have been reported, and little is known about their behavior. We report a new case of localized malignant mesothelioma with the microscopic appearance of diffuse malignant mesothelioma, but without any evidence of diffuse spread. A 54-year-old man, a former smoker, with a brief history of asbestos exposure for 3 months, presented with a severe right chest pain and a swelling in the same area. Chest-computed tomography (CT) showed a 4.5 cm extra pleural tumor with a smooth surface, located in the right anterior chest wall, and destruction of the 5th rib. A CT-guided needle biopsy revealed malignant mesothelioma. Detailed examinations revealed a resectable solitary localized mass with no distant metastasis. The patient underwent operation, a tumorectomy, plus a combined resection of the chest wall and part of the right middle lobe. A complete en bloc resection was achieved. Pathology revealed localized malignant mesothelioma, biphasic type. Immunohistochemical findings confirmed the mesothelial feature. Localized malignant mesothelioma should be distinguished from diffuse malignant mesothelioma because of its different biological behavior, and in the former complete resection it is associated with a good prognosis.