Pleura, histology

Adult Still s disease presents with seronegative polyarthritis, febrile attacks, lymphadenopathy, skin symptoms, hepatosplenomegaly, jaundice and involvement of the pleura and pericardium. The liver is enlarged in about 30% of patients transaminases may be slightly elevated. Periportal lymphocytic infiltrates and Kupffer cell proliferation can be demonstrated histologically. (68, 69)... 

Although malignant mesotheliomas are usually regarded as tumors of the peripheral pleurae or the peritoneum, they also are seen in the mediastinum, where they likely originate from hilar reflections of the pleural surfaces. The immunophenotype of mesothelioma features keratin reactivity in all of its histologic variants, including the purely epithelioid form, and the same is potentially true of calretinin, WT-1, and podo-planin. " Vimentin coexpression also may be seen in roughly 50% of mesothelioma cases, and there is... 

Thymomas may occur in the pleura and can be confused with mesothelioma. These neoplasms may be confused with a sarcomatoid mesothelioma with a heavy lymphoid infiltrate or with a lymphohistiocytoid mesothelioma. None of the cases presented by Moran and coworkers showed radiographic evidence of a mediastinal tumor, however 6 cases showed histologic features of a mixed (lymphocyte-epithelial) thymoma. The neoplastic thymic epithelial cells express keratin and CD5. 

Immunohistochemistry is a valuable technique used to accurately diagnose primary and metastatic tumors of the lung and pleura. As with all adjuvant diagnostic pathologic techniques, the results of immunohistochem-ical tests must be correlated with histological, histo-chemical, and ultrastructural observations and with clinical observations. 

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