Diffuse pigmented villonodular synovitis of the foot and ankle treated with surgery and radiotherapy.

(SBQ12FA.101) A 33-year-old female has had three years of right ankle pain that has been refractory to conservative management. You obtain an x-ray and MRI, which are shown in Figures A-C. Based on these imaging findings, what is the most likely diagnosis?

(SBQ12FA.102) Figures A is the MRI image of a 31-year-old female who presents with complaints of worsening ankle pain and limited motion for the past 10 months. She denies any trauma to the ankle. She ambulates without issue but admits to recurrent swelling and redness of the ankle. She is afebrile and CBC, ESR, and CRP are unremarkable. She underwent an aspiration which revealed 1,100 WBCs with 40% PMNs and >50,000 RBCs. She undergoes a biopsy of the lesion and the histologic finding is seen in Figure B. Which is the most appropriate next step in management?