Extrapleural Locations Research Articles

Solitary fibrous tumor of the kidney

Solitary fibrous tumors are rare spindle cell neoplasms usually arising in the pleura. They have, however, also been reported at extrapleural locations. Solitary fibrous tumor (SFT) of the kidney is rare. Despite its rarity, histological diagnosis of solitary fibrous tumor is crucial to avoid misdiagnosis with other more aggressive tumors arising in the kidney. We report a solitary fibrous tumor of the left kidney that presented as a malignant tumor in a 51-year-old woman, and include clinical and radiographic findings. The tumor was well circumscribed and composed of spindle cells in a collagenous stroma. Immunohistochemistry showed reactivity for vimentin, CD 34, BCL-2 protein and CD99. Immunohistochemical stains for cytokeratin, S-100, desmin, alpha-smooth muscle actin and HMB-45 were negative. A diagnosis of SFT was made based on light microscopy and immunohistochemistry.

Solitary Fibrous Tumor of the Auditory Canal

Solitary fibrous tumor (SFT) is an uncommon spindle cell neoplasm of increasing incidence that was originally described to be of pleural origin; however, more recently, SFT has been reported in extrapleural sites, including the orbit, liver, salivary glands, tongue, nose, paranasal sinuses, larynx, retroperitoneum, meninges, and thyroid. The increase in the number of SFTs does not necessarily mean increased incidence of this tumor but rather an increased understanding of this tumor, especially recognition of this tumor in extrapleural locations, which has been aided by immunohistochemical analysis. We report a case of SFT in the auditory canal, which to our knowledge has not been previously reported, as evident by morphologic findings and immunophenotype.

Bcl-2 EXPRESSION IN PLEURAL AND EXTRAPLEURAL SOLITARY FIBROUS TUMOURS

This study evaluated the immunoreactivity for bcl-2, a molecule involved in the control of programmed cell death, in cases of pleural (14) and extrapleural (2) solitary fibrous tumour (SFT), malignant mesotheliomas of different histological types, and a variety of extrapleural CD34-positive and CD34-negative spindle-cell tumours. In all SFTs, strong and diffuse immunostaining was demonstrated with anti-bel-2 antibody, sharply contrasting with the complete lack of staining observed in all mesotheliomas. The specificity of immunodetection of bcl-2 in SFT was confirmed by immunoblot analysis, showing a band consistent with the bcl-2 protein. At extrapleural locations, strong bcl-2 immunoreactivity was observed in Schwannoma (2/3 cases), synovial sarcoma (4/4 cases), and all cases of CD34-positive gastrointestinal stromal tumour (GIST; 10/10 cases). Most sarcomas were bcl-2-negative. Lack of bcl-2 expression was demonstrated in tumours which can pose problems in the differential diagnosis of SFT and can exhibit haemangiopericytoma-like features, including haemangiopericytoma (3 cases), dermatofibrosarcoma protuberans (16 cases), and deep-seated fibrous histiocytoma (3 cases). The constitutive expression of bcl-2 in SFT widens the spectrum of available markers for these tumours, providing a useful adjunct to their differential diagnosis in difficult cases at pleural and extrapleural sites, and contributing to the understanding of their histogenesis and molecular pathogenesis.

Solitary fibrous tumour arising at unusual sites: analysis of a series

Solitary fibrous tumours ('pleural fibromas') are well-recognized in the pleura, but their rare occurrence at other sites has only become appreciated in recent years, as a consequence of which extrapleural examples often go unrecognized or misdiagnosed. Eight cases (three peritoneal, two retroperitoneal, two intrapulmonary and one mediastinal) are presented herein. All but one presented in adulthood, and three were asymptomatic chance findings. Size ranged from 0.8 to 26 cm in maximum diameter. To date, none has behaved in an aggressive fashion. Histologically, these lesions are entirely comparable to their pleural counterparts, and accurate diagnosis is largely dependent on appreciation of their potential extrapleural location. Immunohistochemistry in seven cases favoured myofibroblastic/fibroblastic differentiation, in keeping with the putative submesothelial origin of these lesions.

Incomplete Border Sign of Extrapleural Masses

WHEN an extrapleural mass is seen partially<i>en face</i>, it may simulate a pulmonary parenchymal lesion. However, the presence of an incomplete border is a clue to the true nature of the mass.¹ <h3>Report of a Case</h3> A routine chest x-ray film (posteroanterior view) of a 21-year-old man showed a large lesion in the left midlung field with an incomplete border sign laterally, indicating an extrapleural mass (Fig 1). The oblique view showed typical signs of an extrapleural mass (Fig 2). The presence of destructive changes in the fourth rib confirmed its extrapleural location. This lesion appeared to arise from the fourth rib at the costochondral junction. The preoperative diagnosis was a chondrosarcoma of the rib; this was confirmed at surgery. The tumor was completely removed en bloc, along with the third and fifth ribs. The surgical defect was closed with Teflon mesh, and the patient made an uneventful