How Do I Find Out Who Should Be Treating My Sister Who Has Cysts?

Hi. My sister has a GCT behind her ear. She has had two surgeries two remove it over the last month or so and they now need to take an MRI to see how deep it may have gone to be sure they've gotten it all. The frozen sections they've taken indicate there is more and the pathology reading indicate it is benign. My concern is that the surgery has been (and will again be) performed by a plastic surgeon and not a surgeon specilizing in oncology and this tumor type. How do I find out who should be treating her? We live in CT and can go into NYC or Yale, New Haven.