Sino-orbital Granulocytic Sarcoma Causing Bilateral Proptosis As an Initial Manifestation of Acute Myelogenous Leukemia (AML): A Case Report

Granulocytic sarcoma is a manifestation of myelogenous leukemia, which means a solid mass consisting of primitive precursors of the granulocytic series of white blood cells. We present CT and MR imaging findings of bilateral sino-orbital granulocytic sarcoma in a 22-month-old boy. The mass involved bilateral orbital fossa which resulted in bilateral proptosis. Moreover, the mass extended to the almost skull base including paranasal sinuses, maxilla, temporal bone, zygomatic bone, sphenoid bone, ethmoid, and palatine bone. The adjacent dura was continuously thickened and the lower half of cavernous sinus was also involved. The patient was diagnosed as AML (M5) with t(8,21) translocation through a chromosome study from the bone marrow.