Solitary fibrous tumor of the pleura is typically benign. True or false?

• A. True
• B. False
• C. Usually malignant
• D. Unknown

Answer: (A)

Solitary fibrous tumor of the pleura is most often a benign neoplasm. It arises from the pleural surface and, when completely removed, typically yields an excellent prognosis with cure in many cases. A minority of these tumors behave malignantly, showing features such as higher cellularity, mitotic activity, necrosis, and infiltrative margins, and they can recur or metastasize. Because the majority are benign and curable with complete resection, the statement that it is typically benign is correct.