Radiological Case: Giant Solitary Fibrous Tumor of the Pleura

Erica Rego; Brian A. Solomon, MD

Disclosures

Appl Radiol. 2018;47(9):41-43. 

In This Article

Discussion

Solitary fibrous tumors of the pleura (SFTP) are rare, slow-growing neoplasms, initially described in 1870 by Wagner and further characterized by Klemperer and Rabin in 1931.[1,2]

The tumor is of unknown etiology and there is no known association with asbestos exposure.[3] The incidence is approximately 2.8/100,000 with 800 reported cases to date.[2] The peak incidence is in the 5th to 8th decades, with no sex predilection. The giant type of fibrous pleural tumors are defined as occupying greater than 40% of the hemithorax and are especially rare, accounting for less than 5% of pleural neoplasms.[4]

These tumors are typically benign, slow growing lesions, with malignancy occurring in less than 20% of cases. Previously thought to arise from the mesenchymal of the submesothelial cells of the parietal pleura,[5] giant solitary fibrous tumors have now been reclassified by the World Health Organization Classification of Tumors. They are now considered part of a broader class of soft tissue neoplasms of fibroblastic and myofibroblastic origin and can arise from virtually any part of the body.[6] The lesions that arise from the pleura are often encapsulated within a thin membrane, which consists of collagen covered by normal mesothelial cells. The tumor is attached to the pleura by a highly vascular pedicle in 38–42% of cases. The base of the tumor is on the visceral pleura in about three quarters of the patients.[5] Malignant tumors are often necrotic with hemorrhage, and they may also result in pleural effusion and adjacent structural invasion.[7]

SFTP are often asymptomatic and tend to present secondary to mass effect on adjacent structures, resulting in nonspecific thoracic symptoms including chest pain, dyspnea, cough, and more rarely hemoptysis. Extrathoracic symptoms have also been reported; these include weakness, fever, weight loss, nocturnal sweating, chills, digital clubbing or hypertrophic osteoarthropathy.[3] Hypoglycemia has also been reported related to the production by the tumor of insulin-like growth factor II (IGF-II), which causes an increased glucose utilization and an impaired growth hormone counter-regulatory response to hypoglycemia.[8,9]

Treatment is based on complete surgical resection, which is curative in nearly all benign lesions and approximately half of malignant ones. Pedunculated tumors can be safely resected with a wedge resection of the lung, but large sessile tumors often require lobectomy or pneumonectomy. Surgical resection, however, is often complicated by the extensive bronchial and systemic arterial supply. In cases involving systemic arterial supply to the tumor, catheter directed embolization may be helpful in reducing the blood supply and risk of perioperative hemorrhage.[5] In many cases, the large tumor burden can also result in chronic compressive atelectasis and, therefore, postoperative expansion edema is a known complication.[9]

The CT appearance of an SFTP is often that of a well-circumscribed lobular homogenous mass often demonstrating marked heterogeneity and necrosis as well as atelectasis and compression/displacement of adjacent structures.[4] Pleural effusions are relatively rare, occurring is less than 10% of patients.[10]

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