A 25-year-old man has had right knee pain with "popping and catching" for the past 2 years. On examination, there is a reduced range of motion at the right knee, but no tenderness or swelling. MR imaging reveals a 3-cm mass in the anterior joint space. Arthroscopic surgery with partial synovectomy is performed, and a nodular, encapsulated mass is removed. Microscopic examination of the mass shows synoviocyte-like tumor cells in a hyalinized stroma containing osteoclast-like giant cells and hemosiderin. An antagonist to which of the following growth factors is most useful in treating this lesion?
High-Yield Explanation
A tenosynovial giant cell tumor (formerly called pigmented villonodular synovitis) is the most common soft tissue tumor of the hand but can occur around the knee as either a localized or diffuse proliferation. An acquired translocation placing the coding sequence for M-CSF adjacent to the promoter of the collagen COL6A3 gene is found in these lesions. Though histologically benign, lesions can be locally aggressive and extend into the adjacent bone and soft tissue. The other listed options are not part of the pathogenesis of this lesion.