My Mother Has Been Dx With Thrombocytosis With Jak 2

My mother has been dx with thrombocytosis with Jak 2 mutation, previous bone marrow was negative for leukemia. However her WBC count now is 30 and she is complaining of severe pain in her right leg behind the knee, radiating down that leg. The pain is a shooting pain, and the ER doctor r/o DVT, Pathological fracture and gout. It's too painful to stand on this leg, despite going home on Norco for pain. What do you think is wrong with her?