Isolated myeloid sarcoma of the temporal bone: As the first clinical manifestation of acute myeloid leukemia in a patient of down’s syndrome

Abstract Introduction Leukemia is the most common malignancy of childhood but myeloid sarcoma is a rare presentation of underlying leukemic disorder. Myeloid sarcoma (MS) is a rare tumor composed of proliferation of myeloid precursors at extramedullary sites. Presentation of case We report an unusual case of myeloid sarcoma involving the temporal bone in a young male child who presented with a large mass involving the left temporal region. This lesion was the initial presentation which led to further diagnosis of acute myeloid leukemia in our case. This case report brings awareness to the diverse extramedullary manifestations of isolated myeloid sarcoma, as well as the importance and difficulties that are associated with establishing a rapid diagnosis and initiating treatment. Discussion They can arise de novo or in association with hematological malignancies, most commonly acute myeloid leukemia (AML-M2). Clinically, it can masquerade as an abscess, cutaneous ulcer, or as a mass lesion. Morphologically, MS can mimic a variety of small round cell tumors including lymphomas, neuroblatoma and rhabdomyosarcoma. The occurrence of this tumor usually heralds AML or the onset of the blastic phase of chronic myeloid leukemia. Early recognition of this rare entity is important, because early aggressive chemotherapy and focal irradiation can cause regression of the tumor and thus improve patient longevity. Conclusion The possibility of MS should be considered when dealing with unusual lymphoma like neoplasms that cannot be categorized as any of the Non-Hodgkin lymphoma subtypes and small blue round cell tumors.