Clinicopathological Features of Solitary Fibrous Tumors of the Pleura: a Case Series and Literature Review

Abstract

We assessed the clinicopathological features of solitary fibrous tumors of the pleura in a case series comprising 30 patients (20 women, 66.6%) with a mean age of 58.39 years. Forty-five percent of the cases were asymptomatic. In 70% of the cases the tumors arose in the visceral pleura. Twenty percent presented multiple tumors, a finding that was associated with intrapulmonary localization and malignant behavior (P<.0001) Histology revealed low cell density in 15% of the cases, moderate density in 50%, and high density in 35%; further findings showed atypia in 45% of the cases, necrosis in 25%, and hemorrhage in 15%. More than 4 mitoses per 10 high-power fields were noted in 30% of the cases. Immunohistochemistry results were positive for vimentin in all cases; cells were CD34+ in 85% of the cases, BCL2+ in 65%, and CD99+ in 40%. Findings for keratin and protein S100 were negative in all cases. Malignant biological behavior (local recurrence and metastasis) was observed in 4 cases, 2 of which were CD34-. Solitary fibrous tumors of the pleura are uncommon neoplasms with unpredictable biological behavior; follow-up should therefore be based on early detection of recurrence or metastasis.