This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
50-year-old, presents with enlarged knuckles and large subcutaneous nodules near her elbows. Her proximal interphalangeal (PIP) joints are hyperextended and her distal interphalangeal (DIP) joints are flexed. If the nodules were biopsied, which of the following would best describe their likely histological appearance? 
Select and explain. 
A. Amorphous crystalline mass surrounded by macrophages, B. Cystic space caused by myxoid degeneration of connective tissue, C. Darkly pigmented synovium with an exuberant, villous growth, D. Fibrinoid necrosis surrounded by palisading epithelioid cells
D: Fibrinoid necrosis surrounded by palisading epithelioid cells
Answer: D: Fibrinoid necrosis surrounded by palisading epithelioid cells 
Explanation: Swan-neck deformity (PIP joints hyperextended and DIP joints flexed), enlarged knuckles, and subcutaneous nodules are classic clues for rheumatoid ahritis. The subcutaneous rheumatoid nodules are composed histologically of areas of fibrinoid necrosis surrounded by palisading epithelioid cells.Gout tophi are amorphous crystalline masses surrounded by macrophages.Ganglion cysts are small cystic spaces caused by myxoid degeneration of connective tissue.Pigmented villonodular synovitis causes darkly pigmented synovium with exuberant villous growth.