Spindle cell tumors of the pleura: Differential diagnosis
ABSTRACT Spindle cell tumors that arise in or metastasize to the pleura must be thoroughly evaluated to arrive at a definitive diagnosis. Malignant mesothelioma is the most common tumor arising in the pleura, but metastatic tumors to the pleura occur more frequently. Additionally, many tumors arising in the lung and surrounding tissues involve the pleura. It is crucial to arrive at a correct diagnosis since many of these neoplasms show different prognoses and require varying treatment modalities. Sarcomatoid malignant mesothelioma is a rare tumor that arises in the pleura, and can be confused with numerous tumors arising in or metastasizing to the pleura, including synovial sarcoma, metastatic sarcomatoid carcinoma, metastatic melanoma, thymoma, renal cell carcinoma, localized fibrous tumor, leiomyosarcoma, and other types of sarcoma. Desmoplastic malignant mesothelioma is a fibrous sarcomatoid variant of malignant mesothelioma, and is occasionally mistaken for chronic fibrous pleurisy. Here, we review morphological, clinical, histological, immunohistochemical, ultrastructural, and molecular methods that aid in the diagnosis of spindle cell tumors of the pleura, and we provide specific examples of patients in which this multi-modal approach proved to be helpful.
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ABSTRACT: Sarcomas constitute a heterogeneous group of rare tumors that in recent years have been shown by cytogenetic analysis to have a remarkably high incidence of specific and primary alterations. These genetic alterations not only have guided molecular studies in establishing the underlying genes involved, thereby yielding important pathogenetic information, but have also provided clinicians with a valuable tool to add to their diagnostic armamentarium. The addition of molecular cytogenetic (fluorescence in situ hybridization [FISH]) and molecular approaches (reverse transcriptase-polymerase chain reaction [RT-PCR]) has further enhanced the sensitivity and accuracy of detecting nonrandom chromosomal imbalances and/or structural rearrangements in sarcomas, including assessment in formalin-fixed, paraffin-embedded tissues. Poorly differentiated sarcomas represent a significant challenge to the pathologist as these neoplasms lack an identifiable hematoxylin and eosin-stained phenotype and often have lost diagnostic immunohistochemical or ultrastructural features as well. In contrast, primary cytogenetic changes and associated molecular events such as the 11;22 translocation in Ewing sarcoma are retained as a given tumor metastasizes or becomes less differentiated, as their presence appears to be vital for sustaining neoplastic transformation. Consequently, demonstration of characteristic, tumor-specific chromosomal aberrations is especially useful in the management of poorly differentiated sarcomas.Ultrastructural Pathology 01/2008; 32(2):63-71. DOI:10.1080/01913120801897141 · 1.13 Impact Factor
Article: Problems in mesothelioma diagnosis[Show abstract] [Hide abstract]
ABSTRACT: Many centres are now seeing increasing numbers of patients with malignant mesothelioma. This presents pathologists involved in making the diagnosis with a number of problems, which can be divided into those encountered in making the distinction between mesothelioma and benign changes and those experienced in separating mesotheliomas from other types of epithelial and connective tissue tumours. Immunohistochemistry plays a major role in helping to make the diagnosis, but it should be interpreted with due regard to the clinical setting and radiological features, and with a knowledge of the wide morphological variations seen in mesothelioma. This review identifies some of these problems and addresses the uses and limitations of immunohistochemistry in different situations. It includes a discussion of some of the less common variants of mesothelioma and other pleural-based tumours that enter into the differential diagnosis.Histopathology 12/2008; 54(1):55-68. DOI:10.1111/j.1365-2559.2008.03178.x · 3.30 Impact Factor
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ABSTRACT: The differential diagnosis of pleural sarcomatoid mesothelioma (SM) from lung sarcomatoid carcinoma (LSC) invading parietal pleura and chest wall is a challenging issue. The aim of this study was to identify useful antibodies that can be used for the differential diagnosis of pleural SM from LSC. Forty-five cases of pleural SM and 27 cases of LSC were immunohistochemically analysed by using 15 commercially available antibodies, including D2-40 and antibodies to calretinin, thrombomodulin, Wilms' Tumour 1, carcinoembryonic antigen (CEA), Napsin A, thyroid transcription factor (TTF)-1, pan-cytokeratin, CAM5.2, epithelial membrane antigen, Ber-EP4, MOC-31, alpha-smooth muscle actin, h-caldesmon and desmin. The results revealed that D2-40 positivity was significantly higher in pleural SM (86.7%) than in LSC (25.9%). The positivity of the adenocarcinoma markers, including CEA, Napsin A, and TTF-1, was low even in LSC. Evaluating the positivity and degree of staining of the well-known mesothelial marker D2-40 could be applied to differentiate pleural SM from the sarcomatoid component of LSC, in addition to assessing clinical and radiological information.Histopathology 06/2009; 54(6):667-76. DOI:10.1111/j.1365-2559.2009.03298.x · 3.30 Impact Factor