Otorrhea or ear leakage, along with other symptoms happens in leukemic patients when the malignant process has spread to the temporal bone (bone located at the side and base of the skull, even forming a part of the ear).
Another possible scenario, is Necrotizing external otitis (infection of outer ear has spread to temporal bone as a complication, leading to complain of severe ear pain that worsens at night, and ear leakage).
This complicated outer ear infection, usually, happens in adults with compromised immune system (as a leukemia sufferer you belong to that category).

Ask for second opinion!
Best wishes!
Marija