This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Joint disorders, Subject name: Orthopaedics
All are Characteristic of SAPHO syndrome except 
Select and explain. 
A. Synovitis, B. Acne, C. Pustulosis, D. Hyperpigmentation
D: Hyperpigmentation
Answer: D: Hyperpigmentation 
Explanation: The syndrome of synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) characterized by a variety of skin and musculoskeletal manifestations. Dermatologic manifestations include palmoplantar pustulosis, acne conglobate, acne fulminans, and hidradenitis suppurativa. Reference: Harrison&;s Principles of Internal Medicine; 19th edition; Chapter 385; Vasculitis Syndromes