Benign and malignant mesothelial proliferation

Malignant mesothelioma (MM) is a rare primary malignant tumor of the surface serosal cells. The diagnosis of MM is challenging with a broad differential diagnosis. For many decades, studies have focused on distinguishing MM from other types of cancer; however, benign mesothelial cell hyperplasia, especially in small biopsies, has emerged as a major problem. The features of pleural lesions are somewhat different from peritoneal diseases, and this article primarily focuses on pleural diseases. Thorough interpretation and correlation of clinical, radiologic, and pathologic findings are essential for a correct diagnosis. © 2010 Elsevier Inc

Silica-induced pleural disease: An unusual case mimicking malignant mesothelioma

PubMedID: 9367490A 57-year-old man with a history of exposure to silica for 32 years presented with pleural thickening of the lower lobe of the left lung and a chronic right-sided pleural effusion without any radiographic evidence of parenchymal nodules in either lung. Light microscopic examination of a left visceral pleural biopsy specimen revealed markedly thickened pleura with fibrosis and macrophages containing birefringent silica and silicates. Occasional rounded intrapleural silicotic nodules were present. The underlying lung tissue did not show fibrosis or silicotic nodules. An energy- dispersive x-ray analysis confirmed the presence of silica. In the absence of lung involvement, this case represents a very unusual pathologic reaction caused by silica and silicates and adds to the clinical differential diagnosis of chronic pleuritis and malignant mesothelioma

Basaloid large cell lung carcinoma presenting concurrently with metastatic uveal tumor

PubMedID: 11282434A 51-year-old man complaining of cough, hemoptysis, and decreased visual acuity was admitted to our hospital. Chest radiography revealed a left hilar mass and pleural effusion in the left hemithorax. In his ophtalmological examination, there was total retinal detachment in the left eye. Ultrasonographic examination and orbital magnetic resonance imaging (MRI) were reported as choroidal metastasis. A computed tomography (CT) confirmed the mass in the left hilum and multiple mass lesions consistent with metastasis in the liver and in the body of 12th thoracic vertebra. Bronchoscopic biopsies revealed large cell carcinoma with basaloid features. He died after 4 months with rapid progression of the disease in spite of combined chemotherapy. Although primary lung cancer with concurrent eye metastasis is an uncommon entity, it should always be kept in mind for patients with ocular symptoms. Copyright © 2001 Elsevier Science Ireland Ltd

Biphasic synovial sarcomas arising in the pleural cavity: A clinicopathologic study of five cases

PubMedID: 8540607Five cases of primary synovial sarcoma of the pleura are presented with a discussion of differentiation from other biphasic malignant neoplasms, most notably malignant mesothelioma. The cases have clinical, histologic, and immunohistochemical features consistent with synovial sarcoma of soft tissue. The average age at initial presentation of the reported patients was 25 years with an approximate range of 9 to 50 years. A large pleural-based intrathoracic mass was identified in each case. Histologic analysis showed a biphasic (mixed) pattern composed of epithelial and spindle cells. The epithelial cells showed cleft-like to tubulopapillary growth with focal intraluminal periodic acid Schiff's (PAS)-positive, diastase-resistant secretions identified in four of the five cases. The spindle cell component was composed predominantly of densely packed, elongated, fusiform cells. Immunohistochemical staining showed positivity with antibodies against cytokeratin, BER.EP4, epithelial membrane antigen, and vimentin in all cases. The patients seem to have fin aggressive course, with four deaths reported within 3 years from initial surgery. These cases represent the first reported cases of primary synovial sarcoma of the pleura and lend further credence to the theory that synovial sarcomas are derived from immature mesenchymal elements, not from synovium

Environmental malignant mesothelioma in Southern Anatolia: A study of fifty cases

PubMedID: 11102295Malignant mesothelioma is a highly aggressive tumor of the serous membranes, which in humans results from exposure to asbestos and asbestiform fibers. Although occupational malignant mesothelioma is still the most common form of this lesion, naturally contaminated soil can play an important role in the development of environmental malignant mesothelioma in some parts of the world. Fifty cases of malignant mesothelioma (MM) from southern Turkey with no occupational history of asbestos exposure were reviewed regarding pathologic and clinical features. A case of hyaline fibrous plaque of the pleura was also included in this series. Histologically the cases were classified as epithelial (36 cases); sarcomatous (7 cases); and biphasic (7 cases). One of the sarcomatous cases was desmoplastic. Ultrastructural examination of the tumor tissue in three cases revealed long-surface microvilli in epithelial cells. Intersititial cells of the lung in one case showed electron-dense asbestos fibers in the cytoplasm. Mineralogical analyses of the lung tissue in three cases of MM and the case of pleural plaque showed high amounts of asbestos fibers most consistent with tremolite and actinolite. The clinical and pathologic features of our cases support that the environmental inhalation of asbestos is still a major health problem in some parts of Turkey

Specificity of MOC-31 and HBME-1 immunohistochemistry in the differential diagnosis of adenocarcinoma and malignant mesothelioma: A study on environmental malignant mesothelioma cases from Turkish villages

PubMedID: 12515999Histological diagnosis of malignant mesothelioma (MM) and differentiation from adenocarcinoma is often difficult. A number of clinical, radiologic, histologic and histochemical criteria have been used as diagnostic aids, but most cases cannot be readily classified on the basis of these characteristics. In recent years, a panel of immunohistochemical antibodies have been increasingly applied for the differential diagnosis of these two tumors. MOC-31 has been recently used as specific for adenocarcinomas while reacting with a minimal number of benign and malignant mesothelial proliferations, and HBME-1 has also been presented as a mesothelial cell marker. In this study, we aimed to show the importance of these two antibodies among the environmental MM cases from Southeastern Turkey. Fifty five cases of MM and twenty adenocarcinomas were included in this study. Histochemical (PAS, PAS-D, mucicarmine) and immunohistochemical (Keratin, EMA, CEA, MOC-31, HBME-1) stains have been performed on each case. Keratin was positive in all cases. EMA stained 50 of 55 MM and all the adenocarcinoma cases. According to our results, dPAS, mucicarmen, CEA and MOC-31 positivity was statistically significant in the diagnosis of adenocarcinoma whereas HBME-1 was demonstrable in most MM cases (52/55) and 11 adenocarcinoma cases. - This study confirmed that in the diagnostic distinction between MM and adenocarcinoma, immunohistochemistry is an important diagnostic tool, however, a panel of antibodies must be used rather than any single antibody. HBME-1 should be included in this panel; MOC-31 can be used where CEA is not available or to doublecheck the reactivity of this antibody