Rare Tumors

Solitary Fibrous Tumor of the Pleura

Author: André Mascarenhas Oliveira - Pathology Resident

Mayo Clinic, Rochester - USA

First described in 19311, solitary fibrous tumor (SFT) is a neoplasm that, in the pleura, seems to originate from the submesothelial connective tissue2,3. SFT has also been described in other sites such as upper and lower respiratory tract, orbit, salivary glands, liver, breast, soft tissues, peritoneal cavity, retroperitoneum, thyroid, meninge and heart4,5,6 .

SFT tends to affect mainly adults during the sixth and seventh decades of life3 and is usually discovered during routine chest X-rays examinations in asymptomatic individuals2. Respiratory symptoms can be present in one-third of patients and include cough, dyspnea, pleuritic pain and hemoptysis2,3. Osteoarthropathy is observed in 10% of cases and hypoglycemia occurs in 5%2. The latter occurs more frequently in tumors located in the right hemithorax3.

SFT arises from visceral pleura in two-thirds of cases and can form large masses that can opacify an hemithorax2. Ipsilateral pleural effusion is observed in 17% of cases3 . Histologically, the most characteristic but not unique pattern is the "patternless pattern" described by Stout7. The neoplasm expresses CD-34 in 80 to 100% of cases but is negative for S-100 and keratin4.

Clinically, malignant mesothelioma and metastatic pulmonary carcinomas are the most important differential diagnoses. Histopathologically, malignant peripheral nerve sheath tumor, mesothelioma, sarcomatoid carcinoma, synovial sarcoma, hemangiopericytoma and fibrosarcoma are important considerations2,3,4,5.

Solitary fibrous tumor is usually a benign neoplasm and the surgical resection is the treatment of choice. However, local aggressiveness and metastasis can be observed in some cases3.

References

1. Klemperer, P & Rabin, C B: Primary neoplasms of the pleura. Report of five cases. Arch Pathol 1931; 11: 385-412.
2. Enzinger, FM & Weiss, SW (eds). Soft tissue tumors 3rd ed. Mosby. St. Louis, Missouri, 1995.
3. England, DM, Hochholzer, L, et al. Localized benign and malignant fibrous tumors of pleura: a clinicopathologic review of 223 cases. Am J Surg Pathol 1989; 13(8): 640-58.
4. Nascimento, AG. Solitary fibrous tumor: a ubiquitous neoplasm of mesenchymal differentiation. Adv Anatom Pathol 1996; 3(6): 388-95.
5. Fletcher, CDM. Anatomic pathologic seminar, case no. 6. Minneapolis, Minnesota, 1997.
6. Flemming, P, Maschek, H, et al. Solitarer fibroser tumor des epikards. Pathologe 1996; 17(2): 139-44.
7. Stout, AP. Tumors of the pleura. Harlem Hosp Bull 1971; 5: 54-57.
8. Khalifa, MA, Montgomery, EA, et al. Solitary fibrous tumors: a series of lesions, some in unusual sites. South Med J 1997; 90(8): 793-9.

Recommended Reference

England, DM, Hochholzer, L, et al. Localized benign and malignant fibrous tumors of pleura: a clinicopathologic review of 223 cases. Am J Surg Pathol 1989; 13(8): 640-58.

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