CXR demonstrating a<unk>  coronal section (the section follows the plane that divides the body in a front and a back half). The<unk>  is indicated by yellow arrows, the central pleural effusion (fluid collection) is marked with a yellow star. Red numbers: (1) right lung, (2) spine, (3) left lung, (4) ribs, (5) descending part of the aorta, (6) spleen, (7) left kidney, (8) right kidney, (9) liver. Micrograph of a pleural fluid cytopathology specimen showing<unk> .Diagnosis of<unk>  can be suspected with imaging but is confirmed with biopsy. It must be clinically and histologically differentiated from other pleural and pulmonary malignancies, including reactive pleural disease, primary lung carcinoma, pleural metastases of other cancers, and other primary pleural cancers. Primary pericardial<unk>  is often diagnosed after it has metastasized to lymph nodes or the lungs.Micrographs showing conventionally-stained<unk>  in a core biopsy (higher magnifications on right). Imaging Diagnosing<unk>  is often difficult because the symptoms are similar to those of a number of other conditions. Diagnosis begins with a review of the patient's medical history. A history of exposure to asbestos may increase clinical suspicion for<unk> . A physical examination is performed, followed by chest X-ray and often lung function tests. The X-ray may reveal pleural thickening commonly seen after asbestos exposure and increases suspicion of<unk> . A CT (or CAT) scan or an MRI is usually performed. If a large amount of fluid is present, abnormal cells may be detected by cytopathology if this fluid is aspirated with a syringe. For pleural fluid, this is done by thoracentesis or tube thoracostomy (chest tube); for ascites, with paracentesis or ascitic drain; and for pericardial effusion with pericardiocentesis. While absence of malignant cells on cytology does not completely exclude<unk> , it makes it much more unlikely, especially if an alternative diagnosis can be made (e.g., tuberculosis, heart failure). However, with primary pericardial<unk> , pericardial fluid may not contain malignant cells and a tissue biopsy is more useful in diagnosis. Using conventional cytology diagnosis of malignant<unk>  is difficult, but immunohistochemistry has greatly enhanced the accuracy of cytology. Biopsy Generally, a biopsy is needed to confirm a diagnosis of malignant<unk> . A doctor removes a sample of tissue for examination under a microscope by a pathologist. A biopsy may be done in different ways, depending on where the abnormal area is located. If the cancer is in the chest, the doctor may perform a thoracoscopy. In this procedure, the doctor makes a small cut through the chest wall and puts a thin, lighted tube called a thoracoscope into the chest between two ribs. Thoracoscopy allows the doctor to look inside the chest and obtain tissue samples. Alternatively, the cardiothoracic surgeon might directly open the chest (thoracotomy). If the cancer is in the abdomen, the doctor may perform a laparoscopy. To obtain tissue for examination, the doctor makes a small incision in the abdomen and inserts a special instrument into the abdominal cavity. If these procedures do not yield enough tissue, an open surgical procedure may be necessary. Immunochemistry Immunohistochemical studies play an important role for the pathologist in differentiating malignant<unk>  from neoplastic mimics, such as breast or lung cancer that has metastasized to the pleura. There are numerous tests and panels available, but no single test is perfect for distinguishing<unk>  from carcinoma or even benign versus malignant. The positive markers indicate that<unk>  is present; if other markers are positive it may indicate another type of cancer, such as breast or lung adenocarcinoma. Calretinin is a particularly important marker in distinguishing<unk>  from metastatic breast or lung cancer. +Typical immunohistochemistry results Positive Negative EMA (epithelial membrane antigen) in a membranous distribution CEA (carcinoembryonic antigen) WT1 (Wilms' tumour 1) MAb B72.3 Calretinin MOC-3 1 Mesothelin CD15 Cytokeratin 5 Ber-EP4 HBME-1 (human mesothelial cell 1) TTF-1 (thyroid transcription factor-1) Podoplanin (PDPN) Claudin-4 Osteopontin Epithelial cell adhesion molecule (EpCAM) Estrogen receptor alpha Mammaglobin Subtypes There are three main histological subtypes of malignant<unk> : epithelioid, sarcomatous, and biphasic. Epithelioid and biphasic<unk>  make up approximately 75-95% of<unk> s and have been well characterized histologically, whereas sarcomatous<unk>  has not been studied extensively. Most<unk> s express high levels of cytokeratin 5 regardless of subtype. Epithelioid<unk>  is characterized by high levels of calretinin. Sarcomatous<unk>  does not express high levels of calretinin. Other morphological subtypes have been described: * Desmoplastic * Clear cell * Deciduoid * Adenomatoid * Glandular * Mucohyaline * Cartilaginous and osseous metaplasia * Lymphohistiocytic Differential diagnosis * Metastatic adenocarcinoma * Pleural sarcoma * Synovial sarcoma * Thymoma * Metastatic clear cell renal cell carcinoma * Metastatic osteosarcoma Staging Staging of<unk>  is based on the recommendation by the International<unk>  Interest Group. TNM classification of the primary tumor, lymph node involvement, and distant metastasis is performed.<unk>  is staged Ia–IV (one-A to four) based on the TNM status.
Mesothelioma
Hemangioendothelioma
Epithelioid hemangioendothelioma
Pulmonary sclerosing pneumocytoma
Large-cell lung carcinoma
Giant-cell carcinoma of the lung
Sarcomatoid carcinoma of the lung
Sarcoma