This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology and Rheumatology, Subject name: Medicine
What is the most likely diagnosis in this 50-year-old woman? 
Select and explain. 
A. Metastasis, B. Onychomycosis, C. Psoriasis, D. Thromboangiitis obliterans
A: Metastasis
Answer: A: Metastasis 
Explanation: Answer A. MetastasisFollowing radiography that revealed a lytic lesion of the terminal phalynx, the firm 2-cm lesion with a scab in the center was biopsied and found to represent a metastasis from follicular thyroid carcinoma.