[A rare cause of otitis externa : Manifestation of myeloid sarcoma in the petrous bone].

A 45-year-old male patient presented with pronounced swelling of the external auditory canal and symptoms of otitis externa which did not respond to conservative treatment. Due to concomitant mastoiditis, mastoidectomy was performed in the later course, which did not provide conclusive histological results. In the absence of improvement, biopsy of the external auditory canal and mastoid revision with repeated pathological analysis were carried out. Ultimately, a myeloid sarcoma representing a relapse of previously remitted acute myeloid leukemia (AML) was identified.