This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Musculoskeletal Radiology, Subject name: Radiology
Sausage finger appearance is seen in- 
Select and explain. 
A. Psoriatic ahritis, B. Rickets, C. Hypehyroidism, D. Addison's disease
A: Psoriatic ahritis
Answer: A: Psoriatic ahritis 
Explanation: Psoriatic ahritis: Involvement of IP joints (interphalangeal) Saucerization of digits Tapering of pharynges Pencil in cup deformity Telescoping sign positive Ahritis multilans / erosive ahritis Opera glass deformity (La Main en Lorgnette) Pencil Cup Deformity