Supplementary Material for: Granulocytic Sarcoma mimicking Cholesteatoma: beware the temporal bone in hematological patients

Granulocytic sarcoma is a myeloid neoplasm that can occur in isolation or in association with acute leukaemia. The temporal bone represents a sanctuary site for myeloid progenitors: granulocytic sarcoma may develop in this location before or concomitant with the onset of acute leukaemia. This atypical presentation with clinical and radiological data that closely mimic those of cholesteatoma often delay an accurate diagnosis. We here present the clinical case of a 28-year-old male with granulocytic sarcoma of the external auditory canal that preceded the relapse of promyelocytic leukaemia.