An important matter of discussion is the malignant potential of this tumor because it may recur locally and even metastasize to distant sites. England et al have defined criteria for malignancy in a large study of 223 cases. These criteria include abundant cellularity, more than four mitoses per ten high-power fields, cytonuclear atypia, large necrotic or hemorrhagic areas, an associated pleural effusion, atypical location, and invasion of adjacent structures. Using these criteria, 12 to 33% of solitary fibrous tumors of pleura were considered as malignant. The most important feature for a good prognosis was the presence of a pedicle and the possibility of complete surgical resection. A long follow-up of such patients is warranted because recurrence can occur as late as 31 years after initial resection.
The natural history of this tumor is not well-known. Because excluding a malignant lesion on imagery alone is difficult, surgical exploration of a solitary pleural tumor usually is carried out shortly after discovery. In the patient in this study who refused surgery, the natural evolution of the tumor was followed by serial CXR. The tumor remained clinically silent but its volume (estimated by planimetry on CXR) increased from 65 to 550 cm over a period of 22 months. This may seem like a fast enlargement, but as far as is known there are no reports about growth rate of solitary fibrous tumors of the pleura, and size of tumor alone is not considered a criteria for malignancy. Finally, in the reported case, there is no clinical or radiological sign of local invasion or distant metastasis. tadanafil
A preoperative diagnosis of solitary fibrous tumors of the pleura by transthoracic cutting needle biopsy allows for histologic analysis and immunohistochemistry to narrow down the differential diagnosis. This minimally invasive diagnostic approach may prevent an unnecessary diagnostic thoracotomy and may help to direct proper treatment. When a solitary fibrous tumor of the pleura is diagnosed, surgical removal usually is straightforward, and resection of functional lung tissue is avoided because the tumor often is pediculated. The complication rate and the functional consequences of this type of surgery are expected to be much lower than when extensive lung resection is contemplated because of possible lung carcinoma, for instance. This is particularly relevant when the preoperative functional or general status of the patient is impaired. When an alternative diagnosis is made with the Tru-Cut needle biopsy, surgeiy may not be the best therapeutic approach. This will prove to be the case for the majority of malignant mesotheliomas and some cases of peripheral lung cancer, for example.
A confident preoperative diagnosis of fibrous tumor of the pleura can be made by histologic and immunohisto-chemical analysis of material obtained by transthoracic Tru-Cut needle biopsy.