Primary granulocytic sarcoma presenting as an external auditory canal mass in a newborn with a draining ear

Summary Granulocytic sarcoma is an uncommon harbinger of myeloproliferative disorders. Known to herald the onset or relapse of hematologic dysfunction, primary granulocytic sarcomas may be the only sign of illness in a patient whose bone marrow aspirate and hematologic work-up return normal. The importance of early recognition of this tumor, often misdiagnosed initially, is that expedient treatment with chemotherapy can greatly reduce the development of systemic disease and improve overall survival. This case is the first report of a primary granulocytic sarcoma presenting with sole finding of an external auditory canal mass in an otherwise healthy newborn twin male. After an extensive immunohistochemical evaluation, the biopsy demonstrated monoblastic sarcoma, an uncommon subtype of granulocytic sarcoma more commonly seen in infants. Further hematologic work-up was negative including normal bone marrow aspirate and biopsy. After 6 months of chemotherapy, repeat bone marrow biopsy were again normal and CT scan showed complete resolution. In a review of the literature, there was one report of leukemic recurrence in an adult female in the nasopharynx, external auditory meatus, and bone marrow.