Symptomatic otologic involvement by leukemic infiltration is unusual, most often occurring in the already-diagnosed leukemic patient as postauricular mass, acute hemorrhagic otitis media, mastoiditis, cranial neuropathy, vertigo, hearing loss, or leptomeningitis. We think ours is the first reported patient whose leukemia presented as atypical mastoiditis and facial paralysis due to granulocytic sarcoma (chloroma). At mastoidectomy, tan lobulated rubbery tumor filled the mastoid antrum and middle ear cleft. Complete remission and full return of facial nerve function was achieved with 2500 R local radiation and systemic chemotherapy. We discuss the role and extent of surgery in atypical acute mastoiditis when unsuspected middle ear and mastoid tumor, with inconclusive intra-operative histopathologic data, is found.