Solitary Fibrous Tumor of the Retroperitoneal Space

A solitary fibrous tumor develops from mesenchymal cells as a pleural neoplasm, but it is also occasionally reported in extrapleural sites. Retroperitoneal tumors are a group of neoplasms located between muscles and the fascia of the posterior abdominal wall and the parietal peritoneum. Their cytology differs from that of urinary tract organs or adrenals. This case report presents a rare solitary fibrous tumor incidentally found during an ultrasound examination. A 54-year-old male underwent urgent surgery for a tumor located in the left retroperitoneal space. The histologic examination confirmed a solitary fibrous tumor with a 5% Ki67 proliferation index, a 1 MF/10 HPF mitotic activity, and CD34-positive immunostains. A solitary fibrous tumor is a rare retroperitoneal tumor. Its symptoms and signs might resemble those of the classical triad of renal cell carcinoma, although the tumor’s growth phase is typically asymptomatic. Intraoperative diagnosis of a solitary fibrous tumor strongly recommends radical excision.

Mesotelioma Intraparenquimatoso Difuso: Uma Apresentação Rara

Pleural mesothelioma is a disease associated with exposure to asbestos. Although rare, it is the most common malignant pleural neoplasm. It is difficult to diagnose and it has a poor prognosis. We report the case of a 62-year-old male patient with a history of prolonged occupational exposure to asbestos, with dyspnea for minor exertion and productive cough, for several months. Imaging studies revealed extensive interstitial involvement with marked thickening of the interlobular and centrilobular septa and tenuous pleural involvement. Several differential diagnoses were considered such as, asbestosis, cryptogenic organizing pneumonia, desquamative interstitial pneumonia, pleuropulmonary metastases, and/or bronchopulmonary infection, but the histological and immunohistochemical results were compatible with pleural mesothelioma - a rare malignant neoplasm, with pleural origin, with a high mortality rate.

Introduction to Pleural Disease

The chapter titled introduction to pleural disease discusses the imaging and clinical features of diseases of the pleura. The pleural space is a potential space located between the visceral and parietal pleural surfaces. Pleural effusion and pneumothorax are the most common manifestations of pleural disease and are caused by a wide variety of disease processes. Pleural thickening may be related to benign or malignant processes. Bilateral discontinuous nodular pleural thickening is characteristic of pleural plaques. Pleural thickening with calcification may also be seen in fibrothorax. Malignant pleural disease may manifest with pleural effusion, pleural nodules or masses, or a combination of the two. There are several CT features suggestive of malignant pleural thickening including circumferential pleural thickening, pleural nodules or masses, involvement of the mediastinal pleural surface, and pleural thickening measuring greater than 1 cm in thickness. Metastatic disease is the most common pleural neoplasm. Mesothelioma is uncommon but remains the most common primary pleural malignancy and is almost always seen in patients with previous asbestos exposure. Pleural abnormalities must be differentiated from pulmonary processes. Pleural masses may exhibit obtuse angles with the adjacent pleural surfaces, displace rather than engulf adjacent pulmonary vasculature, and may exhibit the incomplete border sign.